dy·na·mo \ˈdīnəˌmō\noun (-s) Etymology: short for dynamo machine & dynamoelectric machine; translation of German dynamomaschine & dynamoelektrische maschine 1.: generator 3; especially: a direct-current generator 2.: an individual possessing great or unusual force or energy < this stubby dynamo of thirty-four organizes unions, writes poetry — George Weller >