birr(noun, verb) noun1. the basic unit of money in Ethiopia; equal to 100 centsDefinition categories: quantity2. sound of something in rapid motionSimilar word(s): whir, whirr, whirringDefinition categories: event, sound verb1. make a soft swishing soundSimilar word(s): purr, whir, whirr, whiz, whizzDefinition categories: perception, go, sound