Growth of college power (5)
I believe the answer is:
polyp
'growth' is the definition.
(I know that polyp is a type of growth)
'college power' is the wordplay.
'college' becomes 'poly' (polytechnic).
'power' becomes 'p' (symbol in physics).
'poly'+'p'='POLYP'
'of' is the link.
(Other definitions for polyp that I've seen before include "Coral form" , "Vascular growth" , "Minute reef-building creature" , "Sea creature; small growth" , "Small growth (medical)" .)