Signal assent and point to junction (4)
I believe the answer is:
node
'to junction' is the definition.
(I've seen this before)
'signal assent and point' is the wordplay.
'signal assent' becomes 'nod' (I've seen this before).
'and' means one lot of letters go next to another.
'point' becomes 'e' (compass point).
'nod'+'e'='NODE'
(Other definitions for node that I've seen before include "Point in network where lines intersect or branch" , "Point of intersection" , "Natural swelling of part of a plant or animal" , "Lump at junction" , "Done to a knob" .)