verb / noun
croon
KROON/kruːn/
Soft, smooth singing, often with tender feeling.
The mother croons beside her sleeping baby.

Etymology
Early Scottish use included soft speech or song and low murmuring sounds. The origin is obscure, and the suggested development from lamenting to soft, sad singing remains uncertain.
More examples
- His low croon softened the quiet song.
- The singer crooned into the microphone.
- A gentle crooning drifted from the next room.
Forms
croon · croons · crooned · crooning