Joined with a short line (3)
I believe the answer is:
met
'joined' is the definition.
(meeting is a kind of joining)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for met that I've seen before include "Encountered by chance or arrangement" , "Encountered, came across" , "Got together" , "London police (abbr) - New York Museum of Art (abbr)" , "satisfied" .)