Lock phone before Terry returns (7)
I believe the answer is:
ringlet
'lock' is the definition.
(both can mean a piece of someone's hair)
'phone before terry returns' is the wordplay.
'phone' becomes 'ring' (to ring on the phone).
'before' means one lot of letters go next to another.
'terry returns' becomes 'let' (I can't justify this - if you can you should believe this answer much more).
'ring'+'let'='RINGLET'
Can you help me to learn more?
(Other definitions for ringlet that I've seen before include "sort of lock" , "Curl of hair; butterfly" , "Curl or tendril" , "Hair feature" , "twist of sorts?" .)