Moment meaning : A brief, unspecified amount of time. The smallest portion of time; an instant. Weight or importance. The turning effect of a force applied to a rotational system at a distance from the axis of rotation. (unit) A definite period of time, specifically one-tenth of a point, or one-fortieth or one-fiftieth of an hour. A petit mal episode; such a spell. A fit; a brief tantrum. An infinitesimal change in a varying quantity; an increment or decrement. A quantitative measure of the shape of a set of points.