I. coo 1 /kuː/ BrE AmE verb
[ Date: 1600-1700 ; Origin: From the sound ]
1 . [intransitive] when ↑ dove s or ↑ pigeon s coo, they make a low soft cry
2 . [intransitive and transitive] to make soft quiet sounds, or to speak in a soft quiet way:
‘Darling,’ she cooed.
a cooing voice
—coo noun [countable]
⇨ bill and coo at ↑ bill 2 (3)
II. coo 2 BrE AmE interjection British English
[ Date: 1900-2000 ; Origin: Natural sound ]
used to express surprise:
Coo! That must have cost a lot!