Learner's Dictionary mobile search

Learner's Dictionary

CO

8 ENTRIES FOUND:

Save

CO abbreviation

abbreviation

Learner's definition of CO

Colorado

commanding officer

Comments & Questions

What made you want to look up CO? Include any comments and questions you have about this word.

ASK THE EDITOR

See the answer »

LEARNER'S QUIZZES

Vocabulary Quiz

Test your word power

Take the Quiz »

Name That Thing

Take our visual quiz

Test Your Knowledge »

LEARNER'S WORD OF THE DAY

Learn More »

The Merriam-Webster
Unabridged Dictionary

Online access to a
legendary resource
Log In or Sign Up »

Our Dictionary,
On Your Devices

Merriam-Webster,
With Voice Search
Get the Free Apps! »

Merriam-Webster's
Visual Dictionaries

The new edition of the
remarkable reference
features 8,000
illustrations.
Learn More »

Join Us

Learner's Dictionary
on Twitter »

Learner's Dictionary
on Facebook »

Bookstore: Digital and Print

Merriam-Webster references for Mobile, Kindle, print, and more. See all »

Other Merriam-Webster Dictionaries

Webster's Unabridged Dictionary » Nglish - Spanish-English Translation » Britannica English - Arabic Translation » Visual Dictionary »

Browse the Learner's Dictionary