Branching point (4)
I believe the answer is:
node
'branching point' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for node that I've seen before include "Done (anag.); a knot" , "Intersection in a network" , "Natural swelling of part of a plant or animal" , "Lump at junction" , "Point of intersection" .)