Phone about lines (4)
I believe the answer is:
call
'phone' is the definition.
(I've seen this before)
'about lines' is the wordplay.
'about' becomes 'ca' (abbreviation for 'circa').
'lines' becomes 'll' (I've seen this in other clues**).
'ca'+'ll'='CALL'
(Other definitions for call that I've seen before include "Visit; telephone" , "Phone; cry" , "Ring; name" , "That is enough" , "decision" .)