Style of painting round most of reception (2,3)
I believe the answer is:
op art
'style of painting' is the definition.
(optical art is a type of painting)
'round most of reception' is the wordplay.
'round' becomes 'o' (o is a circular letter).
'most of' means to remove the last letter.
'reception' becomes 'party' (I've seen this in another clue).
'party' with its last letter taken away is 'part'.
'o'+'part'='OP-ART'
(Other definitions for op art that I've seen before include "Nineteen sixties illusory painting style" , "Illusory abstract style" , "abstract works at Tate Modern?" , "that may give the illusion of movement" , "Style of painting having an illusion of movement" .)