What is an electric circuit?

Electric circuit: A closed and continuous path along which electrons from a voltage or current source flows is called an electric circuit. 

For instance, in a torch, a switch provides a conducting link between a battery(a number of cells placed in proper order) and a bulb. When the switch is turned ON, an electric current flows through the bulb and it gives light. Such a continuous and closed path of an electric current is called an electric circuit.

When the switch is turned off or when the circuit is broken anywhere, the current stops flowing through the circuit and the bulb does not glow.