Southern gallery accommodating high-class sculpture (6)
I believe the answer is:
statue
'sculpture' is the definition.
(statue is a kind of sculpture)
'southern gallery accommodating high-class' is the wordplay.
'southern' becomes 's' (abbreviation).
'gallery' becomes 'tate' (Tate Modern, Tate Britain etc).
'accommodating' indicates putting letters inside.
'high class' becomes 'U' (as in U and non-U speech).
'tate' going around 'u' is 'tatue'.
's'+'tatue'='STATUE'
(Other definitions for statue that I've seen before include "Sculpture of person or animal" , "Large figure" , "Sculpture depicting a person" , "A carved or moulded effigy" , "Stone figure" .)