noun, noun which may take the genitive case particle 'no'
branch line; spur line
Refers to a secondary railway line that branches off from a main line. Also used figuratively for other branching connections.
This branch line diverges from the main line.
The station on the branch line is small and quiet.
本線 is the main line of a railway or network, while 支線 is a branch line that splits off from it.
Compound of 支 (branch, support) and 線 (line). The kanji combination directly conveys the meaning of a branching line.