Modus operandi \Mo"dus op`er*an"di\[L.], manner of operating. Often abbreviated to {MO} [1913 Webster]
Mo \Mo\, (Chem.) chemical symbol for the element {molybdenum}. [PJC]
MO \MO\, abbreviation for {modus operandi}, manner of operating; -- often used to refer to the method an habitual criminal uses to perpetrate his crime. [PJC]
-mo \-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[deg], 18[deg], etc. [1913 Webster]
Mo \Mo\ (m[=o]), a., adv., & n. [Written also {moe}.] [AS. m[=a]. See {More}.] More; -- usually, more in number. [Obs.] [1913 Webster] An hundred thousand mo. --Chaucer. [1913 Webster] Likely to find mo to commend than to imitate it. --Fuller. [1913 Webster]