purr
noun /pɜː(r)/
  /pɜːr/
(also purring)
 [singular]- the low continuous sound that a cat makes in its throat, especially when it is happy or comfortable
- the purr of a cat
 
 - a low continuous sound that a machine or vehicle makes when it moves or functions
- the purr of a car engine
 
 - a way of speaking that uses a low and gentle voice, for example to show you are happy or satisfied, or because you want to attract somebody or get them to do something
- ‘Hello darling,’ she said with a purr.