Experiment bringing in uniform to class (8)
I believe the answer is:
tutorial
'class' is the definition.
(I've seen this before)
'experiment bringing in uniform to' is the wordplay.
'experiment' becomes 'trial' (trial is a kind of experiment).
'bringing in' means one lot of letters goes inside another.
'uniform' becomes 'U' (phonetic alphabet: alpha, bravo, charlie etc.).
'u'+'to'='uto'
'trial' enclosing 'uto' is 'TUTORIAL'.
(Other definitions for tutorial that I've seen before include "Study meeting" , "Session of intensive teaching to an individual or small group" , "University study period" , "Seminar" , "Session with a private instructor" .)