Launch, trigger (8)
I believe the answer is:
initiate
I believe this is a double definition.
'launch' is the first definition.
(I know that launch can be written as initiate)
'trigger' is the second definition.
(I know that trigger is a more specific form of initiate)
(Other definitions for initiate that I've seen before include "having special knowledge" , "Originate" , "Start, launch" , "Make something begin" , "Begin or admit into a closed society" .)