What is Crooner?

Crooner definition and meaning on Dictionary terms:
verb (used without object)
to sing or hum in a soft, soothing voice: to croon to a baby.
to sing in an evenly modulated, slightly exaggerated manner: Popular singers began crooning in the 1930s.
to utter a low murmuring sound.

Scot. and North England. to bellow; low. to lament; mourn.

verb (used with object)
to sing (a song) in a crooning manner.
to lull by singing or humming to in a soft, soothing voice: to croon a child to sleep.

the act or sound of crooning.