Noun

• S: (n) birr (the basic unit of money in Ethiopia; equal to 100 cents)
• S: (n) whir, whirr, whirring, birr (sound of something in rapid motion) "whir of a bird's wings"; "the whir of the propellers"

Verb

• S: (v) whizz, whiz, whirr, whir, birr, purr (make a soft swishing sound) "the motor whirred"; "the car engine purred"