Meet in a bar (4)
I believe the answer is:
abut
'meet' is the definition.
(abutting is a kind of meeting)
'a bar' is the wordplay.
'bar' becomes 'but' (I've seen this in other clues**).
'a'+'but'='ABUT'
'in' is the link.
(Other definitions for abut that I've seen before include "Touch upon" , "Cease (from activity)" , "Tuba (anag)" , "Adjoin, touch" , "Adjoin, border" .)