birr

(noun) the basic unit of money in Ethiopia; equal to 100 cents.

(noun) sound of something in rapid motion. Synonyms: whir, whirr, whirring. Examples: "Whir of a bird's wings." "The whir of the propellers."

(verb) make a soft swishing sound. Synonyms: whizz, whiz, whirr, whir, purr. Examples: "The motor whirred." "The car engine purred."