Closed

"Closed" in circuitry generally means a circuit with a full connection from power source to power sink. Think of a piece of wire; an Open loop has no complete circuit, so no electricity flows through it. A Closed loop has a complete circuit, so a current will flow.

Often used with switches, as in "Normally Open" or "Normally Closed"; this says whether or not the circuit is complete while the switch is in its rest state.