/ ˈdaɪnəməʊ; NAmE -moʊ/ noun ( pl. -os )
1.
a device for turning mechanical energy (= energy from movement) into electricity; a generator
2.
( informal ) a person with a lot of energy :
the team's midfield dynamo
She's a human dynamo .
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WORD ORIGIN
late 19th cent.: abbreviation of dynamo-electric machine , from Greek dunamis power.