The point? That is a doll! (6)
I believe the answer is:
barbie
'a doll' is the definition.
(I have seen 'Popular doll' mean 'barbie' so perhaps 'doll' could also mean 'barbie')
'the point? that is' is the wordplay.
'the point?' becomes 'barb' (barb is a kind of point).
'that is' becomes 'i.e.' (synonyms).
'barb'+'ie'='BARBIE'
(Other definitions for barbie that I've seen before include "Figure girl might dress up" , "Popular doll" , "Darwin's feeding party?" , "Empty-headed woman" , "Australian BBQ" .)