A junction, when discussed in the context of transport, is a location where traffic can change between different routes, directions, or sometimes modes, of travel.
The word "junction" derives from Latin iunctus, past participle of iungere, to join.
A road intersection offered opportunities for rest or trade for travellers and merchants.
Towns sprang up to accommodate this; the first such in Europe were probably at intersections of the Roman roads.
Junctions also developed where different modes of transport intersected, e.g. canal and rail.