what is the correct meaning of torque

Torque can be taken as analogus to force. As force is necessary for translational acceleration so on torque is necessary for angular acceleration.

Torque is a rotational force. It is measured in units of force multiplied by a unit of distance. For example, a foot pound is one pound of force at a distance of one foot. It can give you an indication of how strong an engine is (500 ft-lbs is a LOT of torque) or how tight you need to have a bolt. The lug nuts on your wheels need to be about 100 ft-lbs, the bolts on your suspension twice that or more.