coo

UK: 'COO': /ˌsiːəʊˈəʊ/; 'coo': /ˈkuː/

US: /ku/

US: 'coo': (ko̅o̅); 'Coo': (kô′ô)

Inflections of 'coo' (v): (⇒ conjugate)

coos

v 3rd person singular

cooing

v pres p

cooed

v past

cooed

v past p

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

coo¹ /ku/   v., cooed, coo•ing, n. 
v. 

1. to make or imitate the soft, murmuring sound of doves: [no object]
   the baby cooing quietly in the bassinet.
   [~ + object]
   cooing a quiet tune.

n. [countable]

2. a cooing sound.

WordReference Random House Unabridged Dictionary of American English © 2026

coo¹  (ko̅o̅), v., cooed, coo•ing, n. 
v.i. 

1. to utter or imitate the soft, murmuring sound characteristic of doves.
2. to murmur or talk fondly or amorously.

v.t. 

3. to utter by cooing.

n. 

4. a cooing sound.

• imitative 1660–70

coo′er, n. 
coo′ing•ly, adv. 

coo²  (ko̅o̅), interj. [Brit. Slang.]

1. British Terms (used to express surprise or amazement.)

• origin, originally uncertain 1910–15

Co•o  (kô′ô), n. 

1. Place Names Italian name of Kos. 

COO, 

1. chief operating officer.

Collins Concise English Dictionary © HarperCollins Publishers::

coo / kuː/ verb (coos, cooing, cooed)

1. (intransitive) (of doves, pigeons, etc) to make a characteristic soft throaty call
2. (transitive) to speak in a soft murmur
3. (intransitive) to murmur lovingly (esp in the phrase bill and coo)

noun

1. the sound of cooing

interjection

1. an exclamation of surprise, awe, etc

Collins Concise English Dictionary © HarperCollins Publishers::

COO abbreviation

1. chief operating officer