Conversation starter
'conversation starter' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for hello that I've seen before include "I say" , "Meeting greeting" , "Welcome" , "Conventional word of greeting" , "opener?" .)
'conversation starter' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for opener that I've seen before include "First goal in game" , "Kitchen item" , "cricketer, first at the crease?" , "See 1" , "device for getting at the drink" .)