Decided to put page in dictionary? About time (5)
I believe the answer is:
opted
'decided to' is the definition.
(I've seen this in another clue)
'page in dictionary? about time' is the wordplay.
'page' becomes 'p'.
'in' means one lot of letters goes inside another.
'dictionary?' becomes 'OED' (Oxford English Dictionary).
'about' means one lot of letters goes inside another.
'time' becomes 't' (abbreviation).
'p' put within 'oed' is 'oped'.
'oped' going around 't' is 'OPTED'.
'put' acts as a link.
(Other definitions for opted that I've seen before include "Decided as in 10 Across" , "Selected from depot" , "Made choice, selected" , "Depot (anag.)" , "Plumped (for)" .)