em

/em/, n., pl. ems, adj.

n.

1. the letter M, m.

2. Also called mut, mutton. Print.

a. the square of any size of type used as the unit of measurement for matter printed in that type size.

b. (originally) the portion of a line of type occupied by the letter M in type of the same size.

3. See em pica.

adj.

4. Print. having the area of an em quad or the length of an em dash.

[1860-65]

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