EM


Meaning of EM in English

■ noun Printing a unit for measuring the width of printed matter, equal to the height of the type size being used.

↘a unit of measur~ent equal to twelve points.

Origin

C18: the letter M , since it is approx. this width.

Concise Oxford English vocab.      Сжатый оксфордский словарь английского языка.