Joined classes older educator holds (8)
I believe the answer is:
soldered
'joined' is the definition.
(soldering is a kind of joining)
'classes older educator holds' is the wordplay.
'holds' says the answer is hidden in the clue.
'SOLDERED' can be found hidden inside 'classes older educator'.
(Other definitions for soldered that I've seen before include "Joined with metal alloy" , "Joined metals using soft alloy" , "stuck together" , "Joined metals by melting alloys" .)