Corporation's e-ticketing limits start (5)
I believe the answer is:
onset
'start' is the definition.
(both can mean the beginning of something)
'corporation's e-ticketing limits' is the wordplay.
'limits' indicates a hidden word (the answer is surrounded or limited by the clue).
'ONSET' can be found hidden inside 'corporations e ticketing'.
(Other definitions for onset that I've seen before include "Beginning (of something often unpleasant)" , "starting?" , "17 down [ASSAULT]" , "Assault; start" , "origin" .)