Power device of lesser volume (5)
I believe the answer is:
servo
'power device' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'of lesser volume' is the wordplay.
'of' says the answer is hidden in the clue.
'SERVO' is hidden in the letters of 'lesser volume'.
Can you help me to learn more?
(Other definitions for servo that I've seen before include "Mechanism augmenting force or motion" , "Control motor" , "Device amplifying forces" , "Power mechanism" , "Amplifying motor" .)