A circuit breaker or fuse box. Electricity enters the household circuitry through the service panel and is distributed from there through circuit breakers or fuses to branch circuits.
Hold the fixture up to splice the wires. Usually the first wire splice will aid in supporting a small light, but have a helper assist with supporting a large, heavy fixture while making the connections. While still supporting the weight, attach the base to the mounting strap with the screws and tighten the base to the ceiling.
Another switch you may find in your home is a 4-way switch. These have four terminal screws and a fifth green one for a ground wire. Four-way switches are used between two 3-way switches to control lights from 3 or more locations. This can be handy if you have a large room with several entrances requiring light control from multiple locations.
An outlet for tapping into an electrical circuit usually with an appliance plug. Duplex wall receptacles are the most common type, but larger appliance receptacles are also found in household electrical systems.