Best college sheets (5)
I believe the answer is:
cream
'best' is the definition.
(as in 'the cream of the crop')
'college sheets' is the wordplay.
'college' becomes 'c'.
'sheets' becomes 'ream' (I've seen this before).
'c'+'ream'='CREAM'
(Other definitions for cream that I've seen before include "The best part -of the crop" , "Elite; off-white" , "Beat" , "Dairy product" , "Fat-rich part of milk" .)