Tool to select times for admission to A&E? (7)
I believe the answer is:
pickaxe
'tool' is the definition.
(pickaxe is a kind of tool)
'select times for admission to ae?' is the wordplay.
'select' becomes 'pick' (picking is a kind of selecting).
'times' becomes 'x' (x resembles the multiplication or times sign).
'for admission' indicates putting letters inside (inserted letters are let in or admitted).
'x' put within 'ae' is 'axe'.
'pick'+'axe'='PICKAXE'
'to' acts as a link.
(Other definitions for pickaxe that I've seen before include "weapon" , "Mattock" , "long-handled tool" , "it's needed to break new ground" , "which may cause rocky break-up" .)