Greeting round of applause with a wave (9)
I believe the answer is:
handshake
'greeting' is the definition.
(I've seen this before)
'round of applause with a wave' is the wordplay.
'round of applause' becomes 'hand' (as in a 'big hand', a round of applause).
'with' is a charade indicator (letters next to each other).
'a wave' becomes 'shake' (I've seen this before).
'hand'+'shake'='HANDSHAKE'
(Other definitions for handshake that I've seen before include "Physical greeting" , "Friendly gesture" , "introductory offer?" , "Conventional sort of manual greeting" , "acknowledgment" .)