(mainly Australian ) short for moustache (sense 1)
the internet domain name for
Macau
the chemical symbol for
molybdenum
abbreviation for
Missouri
Medical Officer
modus operandi
abbreviation for
mail order
money order
symbol for
megohm
suffix forming nouns
(in bookbinding) indicating book size by specifying the number of leaves formed by folding one sheet of paper ⇒ 12mo, twelvemo, or duodecimo , 16mo or sixteenmo