En
来自Big Physics
late 18th century: the letter N represented as a word, since it is approximately this width.
wiktionary
Abbreviation.
The name of the letter comes from Latin en. The typographic sense dates to 1793.
From French.
From Old English hine
etymonline
en (n.)
name of the letter "N;" in printing (1793), a space half as wide as an em.
en (prep.)
French, "in; as," from Latin in (see in).
