Moment of force:

Here, point O is called as moment centre or fulcrum, and distance x is termed as moment arm.

∴ Moment of force = Force × Perpendicular distance among the line of action of the force and the point or the axis around which moment is needed to be computed.

Moment is a vector quantity and the vector direction is along with the axis about which the moment is taken. In vector algebra, "the moment M of a force F w.r.t. point O is equal to the cross product of the shortest distance of the line of action of the force from the point O and the force F.

If the moment of the force around a point is zero, this means either the force itself is zero or the perpendicular distance among the line of action of the force and the point around which moment is to be calculated is zero that means the force passes through that point itself.