What is meant by an open circuit? Why does electric current not pass in this case?

An open circuit means a circuit which is not complete or is broken (loop). So, the current does not flow in an open circuit.

Open circuit:-

The circuit where the current does not have a closed path to complete the circuit is called an open circuit.

Example:-When we switch off bulb it forms a open circuit, the bulb is turned off.
 

A torch is an example of open circuit.

In this case battery and bulb are not connected.

These are connected by using the switch

In simple language open switch means the switch is of and if we say that switch is closed then the switch is on . if the switch is open the electric current does not pass because current wants continous path to flow.

An open circuit is a circuit which is incomplete and is in off position .

The electric current does not pass in this case because the circuit is incomplete and needs a complete path instead to do so .

An open circuit is a circuit having a break in it like when a wire may be cut. Electric current cant flow because it cant cross the break in the wire as the wire is not in contact. 

open circuit is  circuit in which the switch is in off position.current does not pass in this case because the circuit is broken.