Our British junction boxes for internal use with PVC-sheathed cable are also round plastic boxes fitted with terminal posts (different design though). The boxes have entry points for up to 4 cables, and the commonest types have 3 or 4 terminals.
The 3-way boxes are normally used on circuits for feeding sockets etc. where there's only line, neutral, and earth to connect together.
The 4-way types are most often used on lighting circuits, the extra terminal being used for the switched feed to the light. The 4-cable capacity of the box provides for power in, cable to switch, cable to light, and power out to the next light or junction.
It's also possible to get 6-terminal boxes, which are commonly used for 2-way (American: 3-way) light switching.
