mo

UK: 'MO': /ˌɛmˈəʊ/; 'mo': mail order, money order: /ˌɛm'əʊ/, moment: /'məʊ/

US: (mō)

WordReference Random House Unabridged Dictionary of American English © 2026

mo  (mō), n. [Informal.]

1. Informal Terms moment (def. 1).

• by shortening

-mo, 

1. Printing a suffix occurring in a series of compounds that describe book sizes according to the number of leaves formed by the folding of a single sheet of paper:
   sixteenmo.

• combining form extracted from duodecimo

MO, 

1. method of operation.
2. Place Names Missouri (approved esp. for use with zip code).
3. mode of operation.
4. modus operandi.

Mo, [Symbol, Chem.]

1. Chemistry molybdenum.

Mo., 

1. Place Names Missouri.
2. Monday.

mo., 

1. pl. mos. month.
2. months.

M.O., 

1. mail order.
2. manually operated.
3. Medical Officer.
4. method of operation.
5. mode of operation.
6. modus operandi.
7. money order.

m.o., 

1. mail order.
2. modus operandi.
3. money order.

Collins Concise English Dictionary © HarperCollins Publishers::

mo / məʊ/ noun

1. 
   short for moment1
2. 
   short for moustache1

WordReference Random House Learner's Dictionary of American English © 2026

MO,  an abbreviation of:

1. method or mode of operation.
2. Place Names Missouri.

Mo.,  an abbreviation of:

1. Place Names Missouri.
2. Monday.

mo., pl. mos.  an abbreviation of:

1. month.

M.O.,  an abbreviation of:

1. method or mode of operation.
2. modus operandi.
3. money order.

m.o.,  an abbreviation of:

1. mail order.
2. modus operandi.
3. money order.

Collins Concise English Dictionary © HarperCollins Publishers::

MO abbreviation

1. Missouri
2. Medical Officer
3. modus operandi

Collins Concise English Dictionary © HarperCollins Publishers::

Mo symbol:chemical

1. molybdenum

Collins Concise English Dictionary © HarperCollins Publishers::

-mo suffix:forming_nouns

1. (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

Etymology: abstracted from duodecimo

Collins Concise English Dictionary © HarperCollins Publishers::

Mo. abbreviation

1. Missouri

Collins Concise English Dictionary © HarperCollins Publishers::

m.o., MO abbreviation

1. mail order
2. money order