Other forms: coos, cooing
To coo is to make the soft low sound of a pigeon. Pigeons cooing, a soft coo, cooing in the eaves.
The sound is low, soft and repeated, and it is what wood pigeons and doves do — the wood pigeon's five-note call is one of the most recognisable sounds of a British summer. Applied to people it means speaking softly and admiringly, usually to a baby: cooing over the pram. Note bill and coo, an old phrase for lovers behaving affectionately.
1verbcooTo make the soft low sound of a pigeon.
“Pigeons cooed softly on the window ledge outside my bedroom.”
2verbspeakTo speak softly and admiringly.
“Everyone cooed over the new baby, saying how beautiful she was.”
coo is a soft low sound.
The word is imitative of the sound. Dutch koeren is the same noise heard by neighbours, formed independently.
imitative of the sound. Compare Dutch koeren.
Etymology from Wiktionary, CC BY-SA