The point of having a girl (3)
I believe the answer is:
dot
'the point' is the definition.
('dot' can be a synonym of 'point')
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for dot that I've seen before include "Shorter of the two signals used in Morse code" , "Long-ago year?" , "Internet punctuation mark" , "Spot, speck" , "Small round spot" .)