Begun (7)
'begun' is the definition.
('start' can be a synonym of 'begin')
This is all the clue.
(Other definitions for started that I've seen before include "Made sudden movement from pain or surprise" , "Originated" , "Began; flinched" , "kicked-off" , "Began, jumped" .)
'begun' is the definition.
('commence' can be a synonym of 'begin')
This is all the clue.
(Another definition for commenced that I've seen is " Begun".)