Definition of purrs:
(v) :
(intransitive, of a cat) To make a vibrating sound in its throat when contented or in certain other conditions.
(n) :
The vibrating sound made by a cat in its throat when contented.
(v) :
(intransitive) To make a vibrating throaty sound, as from pleasure.
(v) :
(intransitive, of an engine) To make a low and consistent rumbling sound.
(v) :
(transitive) To say (something) in a throaty, seductive manner.
(n) :
A throaty, seductive sound of pleasure made by a person.