It has a steadying influence in revolution (8)
I believe the answer is:
flywheel
'it has a steadying influence in revolution' is the definition.
The definition suggests a singular noun which matches the answer.
This is the entire clue.
Can you help me to learn more?
(Other definitions for flywheel that I've seen before include "Device storing angular momentum" , "Device used to smooth rotational speeds" , "Regulator used to smooth the running of a reciprocating engine" , "Means of storing power" , "Rotor storing power" .)