Medical instrument to put into large singer Julian (8)
I believe the answer is:
otoscope
'medical instrument' is the definition.
(I know that otoscope is a type of medical instrument)
'to put into large singer julian' is the wordplay.
'put into' indicates putting letters inside.
'large' becomes 'os' (abbreviation for oversize).
'singer julian' becomes 'Cope' (Julian Cope is a singer).
'to' put into 'os' is 'otos'.
'otos'+'cope'='OTOSCOPE'
(Other definitions for otoscope that I've seen before include "Ear examination equipment" , "medical equipment" , "It's used to examine 27 ac" , "instrument coming close to a canal" , "Device for looking in ears" .)