whir also whirr 
/ˈwɚ/ noun
plural whirs also whirrs /ˈwɚ/ noun [count] : the sound made by something that is spinning very fast
▪ the whir of a fan
▪ the whir of a fan
— whir also whirr verb, whirs also whirrs; whirred; whir·ring [no obj]
▪ I could hear the engine whirring. ▪ The fan made a whirring sound.
▪ I could hear the engine whirring. ▪ The fan made a whirring sound.
