Worn machines? (5)
I believe the answer is:
pumps
'worn machines?' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Maybe they are linked in a way I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for pumps that I've seen before include "leading questions" , "Moves fluid or gas by pressure or suction" , "Dancing shoes - may be manned!" , "Cycle attachments" , "Light dancing shoes - force air into" .)