Crossword Genius

Wheel radius to change gradually (7)

Ross

I believe the answer is:

revolve

'wheel' is the definition.
(thesaurus)

'radius to change gradually' is the wordplay.
'radius' becomes 'r' (abbreviation in geometry).
'to change gradually' becomes 'evolve' (I've seen this before).
'r'+'evolve'='REVOLVE'

(Other definitions for revolve that I've seen before include "Go round" , "Rotate" , "Pirouette" , "Turn on an axis" , "stage feature" .)

I've seen this clue in The Telegraph.
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