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• mo
  mo

  noun

  moment.
• Mo
  Mo

  molybdenum.
• MO
  MO

  abbreviation

  method of operation.
• -mo
  -mo

  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.
• mo.
  mo.

  abbreviation

  month.
• Mo.
  Mo.

  abbreviation

  Missouri.
• m.o.
  m.o.

  abbreviation

  mail order.
• M.O.
  M.O.

  abbreviation

  mail order.

mo

¹ American  

[moh] / moʊ /

noun

Informal.

1. moment.

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Mo ² American  

Symbol, Chemistry.

1. molybdenum.

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MO ³ American  

abbreviation

1. method of operation.

2. Missouri (approved especially for use with zip code).

3. mode of operation.

4. modus operandi.

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-mo ⁴ American  

1. 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.

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mo. ⁵ American  

abbreviation

mos plural

1. month.

2. months.

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Mo. ⁶ American  

abbreviation

1. Missouri.

2. Monday.

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m.o. ⁷ American  

abbreviation

1. mail order.

2. modus operandi.

3. money order.

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M.O. ⁸ American  

abbreviation

1. mail order.

2. manually operated.

3. Medical Officer.

4. method of operation.

5. mode of operation.

6. modus operandi.

7. money order.

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MO ¹ British  

abbreviation

1. Missouri

2. Medical Officer

3. modus operandi

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mo ² British  

/ məʊ /

noun

1. short for moment

2. short for moustache

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m.o. ³ British  

abbreviation

1. mail order

2. money order

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Mo ⁴ British  

symbol

1. molybdenum

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Mo. ⁵ British  

abbreviation

1. Missouri

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-mo ⁶ British  

suffix

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

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mo ⁷ British  

abbreviation

1. Macau

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Usage

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 moWhat are some other words related to MO?

• more
• modus operandi
• Missouri

Etymology

Origin of mo¹

By shortening

Origin of -mo⁴

Combining form extracted from duodecimo

Example Sentences

It’s located at the local History Museum on the Square in Springfield, Mo.

From Los Angeles Times • May 12, 2026

The other finalists were Olympic athlete Sir Mo Farah, TV and radio star Craig Charles, and former football manager Harry Redknapp.

From BBC • Apr. 24, 2026

No place in America has more riding on this summer’s World Cup soccer games than Kansas City, Mo.

From The Wall Street Journal • Apr. 6, 2026

“This is the best bookstore ever,” said Mo, who had lived there a while before Gil had to ask her to leave.

From Slate • Mar. 25, 2026

"You can forget Superman—Gilgamesh was the boss. Mo worshipped him. Made us all go to the Metropolitan when they had the big exhibit. So, you were his sword?"

From "City of the Plague God" by Sarwat Chadda

Related Words

• rule of thumb