Centre for computers, say (3)
I believe the answer is:
put
'say' is the definition.
(thesaurus)
'centre for computers' is the wordplay.
'centre for' says to take the centre.
The middle letters of 'computers' are 'PUT'.
(Other definitions for put that I've seen before include "Place; placed" , "Place in a location" , "Set (in place)" , "Place, lay" , "Place in a position" .)