Origins of Em, En, Ex

I’m reaching out for some clarification, although I feel like this has most likely been discussed. I am reading a text in which there is a conversation around Em & En spaces, the usual talk. Em quads are the full height of the font, En quads are half that, etc. Then they referred to the lowercase height as the “ex” height, which I had never seen before. I’ve always seen it written as x-height.

I want to ask “what are the origins of the names Em, En, and Ex. Are they short for something, or abbreviations?” Does anyone have some old printing text that can describe how these spaces were named? Thank you.

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Here is a workingman’s response.

An M quad is a square quad, or piece of spacing material, having the same size as the type size you are referring to. For instance, a 12 pt M quad is 12 X 12 points. It is called that because the uppercase letter M is often cast on this size.

An En quad is half of an Em quad and is approximately the size which uppercase N’s are cast on. So a 12 pt N quad is 6 pts wide X 12 pts high.

The x height is the height of the lowercase letters in a font (not counting letters with descenders like p or y, or letters with ascenders like l or h).

As an aside, the beauty of the quad and space system is that often, quads and spaces of different sizes are interchangeable, so if you run out of one, you can use the other. For instance, if you run out of 12 pt 2M quads you can use 24 pt N quads because they are the same. If you need 6 pt 3M quads you can use 18 pt 3-to-M spaces because they are the same. And there are many more combinations like this.

Hey Geoffrey,

While usage has giving this idea some verisimilitude, I am fairly certain the Em quad is not called so because it is the shape of an M. I believe this is simply a naming device that was used to distinguish the two spaces, and make it easy for apprentices to remember which space is which. We’ve just become so familiar with this that it’s not often talked about. Same with x-height/Ex height. We often say that this is because it’s the height of the lowercase x, but what I’ve been reading (typesetting books for apprentices from 1890–1910) suggest otherwise. There is no mention of M, N, or x being used as a standard for width or height. This is what I’m looking for someone who might have some earlier printing text that describes this.

Uppercase M’s are cast on quads often as an upper limit to design—it’s easiest to do this because its an already available size. But, I have a few M’s in my collection that are bigger than an Em quad, so it’s a move that’s pretty frequently discarded.

A further note is that if Em & En quads followed this system, the grammar rules for Em dashes and En dashes wouldn’t work properly. En dashes often don’t work the way they were intended, because they’re too similar in size to a hyphen.

I could be completely wrong, but I’m interested in finding out how far back we can read about examples of Em, En and Ex dashes to find out.


To quote from ‘Practical Printing’ by John Southward (London 1900):

‘An em is a unit of measure varying with the bodies of types. It is always equal to the depth or body of the type of which the fount is composed. An em is one-half of the em. These names were given to the measures because in book founts the type for the letter “m” was usually exactly as wide as it was deep, and the type for the letter “n” half as wide as it was deep.’
Note too that the term ‘mutton’ is often used for ‘em’, and the term ‘nut’ for ‘en’ - to help verbal/aural differentiation and to prevent misunderstanding in noisy printing workshops!

Correction to my previous post: third sentence should read:

‘An en is one-half of the em.’

I’ve found two more examples, the first from 1905 in which the terms Em & En are used, and there is terminology attached to each fractioned space. All “quads” are referred to as quadrats.

The second, significantly older (1867) seems to support you both, in referring to an Em space as an M space.

However, neither text makes reference to the Em or Em space as being from M or N despite appearances. I’m hoping to find something from late 18th early 19th century.

image: The Printers Manual, 1867

The Printers Manual, 1867

image: Printing, 1905

Printing, 1905

I am looking at Joseph Moxon, Mechanick Exercises on the Whole Art of Printing, originally published 1683-84, second edition edited by Herbert Davis & Harry Carter, published by Dover,1978. On page 170 of this edition, in his discussion of Casting of Letters, etc., Moxon says: “But besides Letters, there is to be cut for a perfect fount (properly a Fund), Spaces thick and thin, n Quadrats, m Quadrats, and Quadrats.” I am guessing that the last Quadrats are 2-em.



Nice, thank you! I’m at 1818, with “The Printers Guide” and I’m seeing Em, En, Ex, Quadrat, and Fount.

I’ll see if I can find this text on my end. With everyone that’s been here, does anyone have an idea then why the e is added?

image: Printers Guide, 1818

Printers Guide, 1818

For posterity, here is an example from Mechanick Exercises that has an example of m & n quadrant being used. This version is from 1683.

image: mechanickexercis00moxo_0_0267.jpg


image: mechanickexercis00moxo_0_0266.jpg


My guess is the “e” was added to clearly distinguish the letters m and n from the spaces em and en. It would certainly reduce confusion when ordering sorts from a foundry.
I have never seen “ex-height” used in place of x-height; that is unambiguous.

In the U.K letterpress industry compositors called an em space a mutton and en space a nut. In a busy composing room it avoided confusion that might be caused by the similar sounding names of em and en.

So the set of spaces in a case would be mutton, nut, thick, mid and thin and hair spaces where companies used the thin copper spaces.

Mutton was used in the US too in earlier days. That’s why the US version of dicing with quadrats was called Jeffing, (from the comic strip Mutt and Jeff).

parallel-imp, I call bs, the Mutt ‘n’ Jeff cartoon was introduced in 1907, and here is a link to an article from The Morning Press, Santa Barbara, CA, 15 April 1904:

image: Screen Shot 2021-03-04 at 10.32.38 PM.png

Screen Shot 2021-03-04 at 10.32.38 PM.png

Fine. So Mutt and Jeff comes FROM printer’s lingo, which would not be unlikely for a news cartoon.
“Calling bs”? Why do you ALWAYS take the most combative take on everything? Is that why you took so much effort to delete past posts?

Hey parallel_imp & Devils Tail (could we get some first names in here, pen names maybe) It’s fine, no worries. Let’s all assume that everyone is well meaning, and that we’re all here for the greater benefit of printing knowledge sharing, and also check before we post to not sound too combative. I’m guilty of as well.

I’m going to follow up to a post from parallel from earlier, talking about the “ex height” instead of x-height. I have an example here somewhere but I’ll have to track it down later.

At this point, I’d say we’re here:

I concede to Geoffry and Kenneth, and am swayed to their side of the argument. I think that as far as we all can see, M & N quads are named for the size of the type that they resemble. The next step would be to find a piece of literature that says “The M-quadrat and N-quadrat are called so because it is convenient to typeset onto existing spacing material” or the opposite “The M-quadrat and N-quadrat are called so because they resemble the side of a M & N.” I think this is going to be hard before 1700 because I would assume that printers manuals weren’t really thinking about posterity, and were more concerned with getting the work done.

Devils Tail Press

Are you back? I hope so. You have been missed by those who appreciate your willingness to share.


The first documented use of Mutton-quad was in Luther Ringwalt’s 1871 American Encyclopedia of Printing (OED). The adventures of Mr. A. Mutt drawn by Bud Fisher was first shown in the San Francisco Chronicle in November 1907. The San Francisco Examiner (Hearst) lured Fisher over in December of the same year, and it wasn’t until early 1908 that Fisher introduced a character from a madhouse, Jim Jeffries, who thought he was a boxing champion. It is highly doubtful that either character was named for any printing term, but rather started with the dictionary definition, of a mutt being a stupid or foolish person, or simpleton. The “Jeff” character was likely named after James Jackson “Jim” Jeffries (April 15, 1875 – March 3, 1953) an American professional boxer and World Heavyweight Champion.

It might be helpful to remember that Ben Franklin worked as
a comp (in a small shop on Saffron Hill, London near to the tube station) for quite a while, dodging creditors back in the US. Comp room legend here has it that he led a strike for extra pay for setting five point, and won!. Once part of Government in the US he initiated a change of names for sizes of paper so no longer Royal or Double Crown, but Eagle and so forth. I think he may well have brought other technical ideas back with him from the UK apart from political ones. He certainly met John Baskerville.

Harrildplaten, that is the idea that I’m chasing, but I’m not finding much traction that far back. I’m going to be in DC later in the year, and I will see if there is some information at the Library of Congress. I think there is a museum for printing as well (currency, I think) and maybe someone there has an idea.

OK, I stand corrected, so how the hell does “jeffing” come from using “muttons” if unrelated to Mutt & Jeff?

In John Johnson’s “Typographia or the Printers Instructor” Vol. 2, 1824, the terms “m-quadrat” and “em quadrat” are both used in the book and with apparently the same meaning. In my opinion, the size of a capital M, is secondary to the definition of an em, given that the definition of a quadrat in general, is that of a square. And the definition of an em is the square of the type body, as others have pointed out.


I believe that. I am 100% certain that quadrats received a name after there creation that we now refer to as Em & En. What I’m curious about is wether Em & En refers to something else, other than the M & N characters. That they could be short for something, or a prefix.

I think that harrlidplaten also has a good assumption, that since printing comes from a European lineage through the settlement of the US, we probably have some terminology that got lost in between. So for a while my research is going to go to European books.

Thank you both.

You’re making a mountain out of a dead horse. You might just want to start paying attention to the information you have already been given, rather than spending more time in search of an alternate truth. The Em-quad and En-quad terms are in reference to the lowercase characters, the traditional width of each being close to the dimensions you discuss. What more do you really need?

Need more? Read:

Typographical Printing-Surfaces, by Legros and Grant, Longmans, Green and Company, London, 1916

Mutton and Nut are largely unknown terms in the US. Both are missing from the American Dictionary of Printing and Bookbinding, W. W. Pasko, Howard Lockwood & Co, New York, 1894. Legros and Grant mention them both on page 55, but give no origin for the terms, which are likely just an alternative sound for m=mutton, and the same for n=nut. Likely originating as a set of slang terms used by workers in a large city plant in England. Most dictionaries list the origins as in the early 20th century. OED doesn’t mention them at all. Nor are they mentioned in late 19th century, early 20th century English manuals Southward or Jacobi.

Remember that Caxton brought printing to England in 1476 only 25 to 35 years after its invention, so English input into common printing terms is almost as old as printing itself.

Devils Tail,

There are several reasons for my research. Em and En have become units of digital space—they are now the standard unit of measurement for the full heigh of the space a font occupies and half that space, same as in hot type, except now they signify an absence of space since no physical object is present. Em is also used as a unit of measurement in coding, and this is causing the definition of this term to change again.

Graphic design has also done an extremely poor job of explaining how these terms have changed in academic settings, to the point where some textbooks flatly say and Em is the same as an “M”, the En is the same as an “n.” I would like to make a concise and definitive timeline for these things so that that shouldn’t happen again in the future. (although it will).

And, in the time since my last post, it seems that there is a concrete (albeit not exciting) reason for Em and En—this is how you would refer to the characters in latin. So that is where the research will go next, and hopefully I can find some more old texts in the meantime.

A wikipedia article, not the most academic of me, but it does show the Latin name of M being “Em” and the Latin name of N being “En”. So if nothing else, there’s that.

image: Latin names

Latin names

Here is a very definitive answer for at least part of this journey. In the 1683 version of Mechanick Exercises this page is seen, which states:

“When they Cast these Spaces or quadrats this Stop is always screwed fast upon the Carriage of the un- der-Half Mold as aforsaid. So that they only fit the upper half Mold on the under, and Cast their Number almost twice as quick as they do the Letters in Matrices.

It is generally observed by Workemen as a Rule, That when they Cast qadrats they Cast them exacty to the Thickness of a set Number of m’s or Body viz. two m’s thick, three m’s thick, four m’s thick, etc. And therefore the Stops aforesaid must all be filed exactly to their several intended thicknesses. The reasbn is, that when the Compositor Indents any Number of Lines, he may have quadrats so exactly Cast that he shall not need to Justify them either with Spaces or other helps.”

Page 174, Mechanick Exercises, Vol 2

What this is saying (or at least how I’m interpreting this) is that when composing spacing material, the compositors would just cast the body for an M, or 2 Ms, or 3 Ms, and then filing several variations of these spacings so that they have a wide range of these spaces to grab at will. So you might have a 2 Em slightly shy, a 2 Em slightly proud, and so on. And that, if correct, would explain mostly all of this forum.

Em quads are (as everyone explained, and I defiantly rallied against) originally cast as the bodies of M. They are called Em and En because this is the proper name for these letters in Latin. They were just cast as material that was intended to be filed, so a range of them existed in the case to grab when needed (like when you really, really need that thin to be the right size but it just isn’t). Later, at an indeterminate amount of time, they are referred to as a Mutton and Nut.

I have a few more things to follow up with. I have a visit to the Henry Ford Museum, to talk about printing technology, a day at the Smithsonian for the same reason, and maybe something will come to the surface there but I’m mostly there for other things.

I also have gotten ahold of two friends, one in Germany, another in Switzerland, to ask their thoughts. We’ll see how it all goes. Thanks everyone for the discourse so far, this has been great and I appreciate it deeply.

image: Mechanick Exercises, page 174

Mechanick Exercises, page 174

Dear Telkaut, as a visitor from the modern digital world, it
might be helpful to add a bit about x-height. Now whilst a good many of the Monotype UK faces have their lower case x centrally on the body in the up - down sense, the old pivotal casting type-foundries ([properly so called) had in the UK their own system of alignment of the face on the body in that same up down sense. Stephenson Blake Ltd had three different alignment standards , with fixed amounts of points allocated below the x-height. This allowed one to set a large Initial capital to start a word maybe in a quite different type face and know the bit of packing adjustment leads required., Their names were Point Art Line, Point Standard line and Point Titling line. This is almost entirely forgotten now, but experiment will show.. In the US, ? I don’t know. For clarity always bear in mind two ‘moulds’ to make type, one for the body, one for the face.

The latin name/pronunciation chart has absolutely nothing to do with the history you are supposing. At this point you have some weird assertion about printing terms that are lost in antiquity, like the word pica, or any number of obsolete terms, and I see you attempting to twist reality to fit your imagined theory, rather than documenting any real facts, or uncovering anything at all. You dismiss documents put in front of you, but prefer to use Wikipedia as a reference to prove that an m is pronounced em. Pure nonsense.


I’m sorry that you feel that way, but I need you to understand two things.

This is a hypothesis. I’m trying to get an idea together, so that I can seek truth through academic sources. Part of that is speculating so that an idea can be formed. If you read anything above, you’d already know that. I’ve also acknowledged all the information presented above, and thanked people for their help, including yourself. All documents presented have been logged for the information they contain.

I’ve already had part of this theory confirmed, but I’m only sharing what is publicly available (wiki) until I know for sure. I have to spend some time in archives to find proper documents to verify what I am writing for.

It’s not for you to judge what my assertions are, or how my time is spent with obsolete terms. This is a democracy, and if you don’t like the freedom of information or sharing, you can find somewhere else where you can be the king of something.

You’re making an imaginary argument for the sake of being right, when no one is trying to dispute you, and all that is being asked for is help. Please moderate yourself in the future.

And last, not one soul said a thing about pronunciation.


Good to hear from you, and thank you. I did not know that, and will research further. I will be speaking about x-height as well. A lot of this research is to talk about how terminology changes over time, and how that leads to all sorts of issues down the road, to no fault of anyone. Adobe products, that simulate things like darkrooms, print shops, and commercial artists studios often aren’t able to interpret terms correctly because the persons developing the software don’t have these experiences. The best example being how leading works in digital typesetting, as opposed to working with hot type.

I don’t think there’s ever going to be a concrete answer to any of these things, but what I would like to do is talk about the technology. terminology, and the history of printing within the context of modern graphic design studies. A lot of students struggle because this connection has become so muddy, with home printing making commercial printing more obscure, and so much of graphic work not being printed.

Heard back from friends in Europe, and not too much there but interesting enough. German/Swiss German is Geviert and Halbgeviert, essentially square and half-square for their version of an Em & En dash. So not much help, but in doing so remembered an interesting side note—European fonts don’t use the same spacing system as ours after a certain point.

A lot of European countries used letterpress much longer than we did (some countries basically skipped phototypesetting—went straight from letterpress to digital) so their technology got a little better, and also you can find things a lot newer. A good example is Dafi’s Grafix proof press.

Teikaut. I had no idea you were so erudite. I stand corrected. There must be a burning need for what you have to offer - em and en - who knew it was such a riveting subject?

It is obvious that you have a lot of reading to do, especially about the transitional period between letterpress and offset printing - which you seem to have skipped over entirely. perhaps when you are finished examining your preconceived ideas you might understand that new technology takes from the old that which it needs, and discards that what is no longer necessary, and attempting to re-insert it is futile because 1) nobody cares (outside of the rapidly disappearing remnants of an industry that was already obsolete 70 years ago), and 2) it is no longer necessary to the industry it parented, and if you haven’t noticed, digital, which is quickly replacing offset and screen printing, which in turn replaced letterpress, has little need for antiquated printing terms. I’m truly sorry that you have so little understanding of that which you are attempting to re-define.

That’s nice Paul, thank you for commenting. I appreciate you being here and for your knowledge.

Hi, Telkaut
I think you might find t more interesting and a lot more academically rewarding to look into the layout of typecases
in years long past. Where for example did they put the long ‘s’ way back then, and how about our long forgotten ‘thorn’.
This latter still echoes today in cafe frontage signs which
read YE Olde Tea Shoppe. Now our friend Will Shakespeare knew what noise to make when he read ‘Ye’
didnt he?. But today the noises aren’t quite right … .

Its taken me a very long time to dredge this from the back recesses of memory, but in the 1950s in a City of London
financial and security printers, I now recall that when wanting to mean 12 point or 6 points of spacing (leads or clumps) had to be added to a forme, maybe particularly when discussing the imposition stage, they usually said ‘pica’ or ‘nomprul’ This latter being a very mangled cockney version of nonpareil. Pica was pronounced ”pyeka” by the way. Whereas at earlier stages in composition much greater precision was required and Ems and Ens came into it. With careful the addition of (say) ”10 point ems” as appropriate. Much confusion came from agency typographers mark up dimensions, where they often just said Ems Assuming we knew they meant 12 point ems!