[ moh ]
/ moʊ /
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Definition of mo

noun Informal.
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Question 1 of 8
On the farm, the feed for chicks is significantly different from the roosters’; ______ not even comparable.

Origin of mo

By shortening

Other definitions for mo (2 of 8)


Symbol, Chemistry.

Other definitions for mo (3 of 8)


method of operation.
Missouri (approved especially for use with zip code).
mode of operation.

Other definitions for mo (4 of 8)


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.

Origin of -mo

Combining form extracted from duodecimo

Other definitions for mo (5 of 8)


plural mos. month.

Other definitions for mo (6 of 8)


mail order.
modus operandi.
money order.

Other definitions for mo (7 of 8)



Other definitions for mo (8 of 8)


Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What else does MO mean?

MO—it’s a multifunctional set of letters. MO is commonly used as an abbreviation for modus operandi, meaning “mode of operating or working.” It’s also commonly a postal abbreviation for Missouri.

You may not always encounter mo in uppercase letters in informal contexts in digital communication. So, two other widespread, popular uses of mo you may encounter are: Mo, a guy’s name, and mo, a dialectical pronunciation of more.

In the U.K. and other English-speaking places around the world, mo is a slang shortening of the word moment.

How is MO pronounced?

[ em-oh ] or [ moh ]

What are some variants of MO?

or M.O. or mo’ or mo

What are some other words related to MO?

Where does MO come from?

The acronym MO is short for modus operandi, an expression directly from Latin meaning “way of operating.” Modus operandi was first recorded in English by the 1650s. The phrase specifically refers to the particular, often characteristic manner someone goes about doing something—later broadened to one’s “style.”

Modus operandi was adopted by early 20th-century criminologists who sought to establish patterns in crimes. These researchers identified criminals on their methods, called the modus operandi system, shortened to MO. As any fan of TV police procedurals can tell you, MO spread as an expression for a criminal’s signature pattern of committing the crime.

Starting in 1831, Mo. was the official postal abbreviation for the state of Missouri, written as MO by 1963.

Mo is also a short form of the common men’s name Muhammad or Mohammed, borne by the likes of the great British-Somali runner Mo Farah.

Furthermore, or should we say furthermo’, mo’ is a pronunciation of more in Black English, which often drops word-final Rs. (English once had, in fact, a word mo that meant “more.”) Mo’ reached the top of the Billboard charts thanks to the Notorious B.I.G.’s 1997 hit song “Mo Money Mo Problems.”

In British slang, mo is also a slang shortening of moment, as in I’ll call you in just a mo!

How is MO used in real life?

MO is a go-to shorthand for modus operandi to describe someone’s style or manner of doing things, e.g., His MO is going to coffeeshops to get his writing done.

Using mo’ for more is common in Black and Southern American English. As rapper Kendrick Lamar raps on his 2017 “XXX.”: “Johnny said books ain’t cool no mo’, no mo’.”

As the official abbreviation for Missouri, MO is very useful when addressing things to or from there.

And as Muhammad is one of the most common men’s names in the world, expect to meet lots of men who go by Mo for short.

Finally, if you’re in the U.K., drop a casual mo for moment if among friends.

More examples of MO:

“Pastry chef shows you his M.O. in the kitchen”

—Inger Sandal, Arizona Daily Star (headline), April 2010

How to use mo in a sentence

British Dictionary definitions for mo (1 of 7)

/ (məʊ) /

noun informal
mainly British short for moment (def. 1)
mainly Australian short for moustache (def. 1)

British Dictionary definitions for mo (2 of 7)


the internet domain name for

British Dictionary definitions for mo (3 of 7)


the chemical symbol for

British Dictionary definitions for mo (4 of 7)


abbreviation for
Medical Officer
modus operandi

British Dictionary definitions for mo (5 of 7)


suffix forming nouns
(in bookbinding) indicating book size by specifying the number of leaves formed by folding one sheet of paper12mo, twelvemo, or duodecimo; 16mo or sixteenmo

Word Origin for -mo

abstracted from duodecimo

British Dictionary definitions for mo (6 of 7)



abbreviation for
mail order
money order

British Dictionary definitions for mo (7 of 7)


abbreviation for
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for mo


The symbol for the elementmolybdenum
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for mo


The symbol for molybdenum.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.