-mo (?). A suffix added to the names of certain numerals or to the numerals themselves, to indicate the number of leaves made by folding a
sheet of paper; as, sixteenmo or 16mo; eighteenmo or 18mo. It
is taken from the Latin forms similarly used;
as, duodecimo, sextodecimo, etc. A small circle, placed after the number and near its top,
is often used for -mo; as, 16°, 18°, etc.
Mo (?), a., adv., & n. [Written also moe.]
[AS. mā. See More.] More; -- usually, more in number. [Obs.]
An hundred thousand mo.
Chaucer. Likely to find mo to commend than to imitate it.
Fuller.
Hear it pronounced