Definition of: phase

(fāz) noun
1. The view that anything presents to the eye; any one of varying distinctive manifestations of an object.
2. Astron. One of the appearances or forms presented periodically by the moon and planets.
3. Physics a In an oscillatory motion, the position and character of a wave at any instant: often measured as an angle, the whole period being regarded as a circle, or 360°. b The instant when the maximum, zero, or other relative value is attained by any cyclical system, as sound or light waves, an alternating electric current, etc. c Any of the homogeneous forms of a given substance that may occur alone, or exist independently as a component of a larger heterogeneous system, as ice in water, water vapor in fog, etc.
4. Biol. a One of the distinct stages in the reduction or division process of a cell. b Any characteristic or decisive stage in the growth, development, or life pattern of an organism.
—to phase out To terminate work on, production of, etc., step by step and according to plan. Also pha·sis (fā′sis). ♦ Homophone: faze. [<NL phasis <Gk., an appearance <phainein make appear]
—pha·sic (fā′zik) adjective