Prize firm invested in mechanical learning (7)
I believe the answer is:
rosette
'prize' is the definition.
(I've seen this before)
'firm invested in mechanical learning' is the wordplay.
'firm' becomes 'set' (both can mean fixed).
'invested in' means one lot of letters goes inside another.
'mechanical learning' becomes 'rote' (I've seen this in another clue).
'set' put inside 'rote' is 'ROSETTE'.
(Other definitions for rosette that I've seen before include "Type of award" , "Ribbon badge for prize-winner" , "Colourful decoration worn by supporters" , "Mark of affiliation" , "Ribbon in a cluster as an award" .)