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.

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 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.


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?

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.

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.

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.

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.

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.

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!