A brief, indefinite interval of time. A specific point in time, especially the present time: He is not here at the moment. A particular period of importance, influence, or significance in a series of events or developments: a great moment in history; waiting for her big moment. Outstanding significance or value; importance: a discovery of great moment. A brief period of time that is characterized by a quality, such as excellence, suitability, or distinction: a lackluster performance that nevertheless had its moments. Philosophy An essential or constituent element, as of a complex idea. Philosophy A phase or an aspect of a logically developing process. Physics The product of a quantity and its perpendicular distance from a reference point. Physics The tendency to cause rotation about a point or an axis. Statistics The expected value of a positive integral power of a random variable. The first moment is the mean of the distribution.