Sound of a happy tabby (4)

I believe the answer is:

purr

(Other definitions for purr that I've seen before include "Sound of happy animal" , "Make contented sound like cat" , "Low vibratory sound" , "Sound of a happy mog" , "Happy feline sound" .)

I've seen this clue in the Newsday and the LA Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.