noun any appearance or aspect of an object of mental apprehension or view; as, the problem has many phases.
2. phase ·add. ·vt to disturb the composure of; to disconcert; to nonplus.
3. phase ·noun that which is exhibited to the eye; the appearance which anything manifests, especially any one among different and varying appearances of the same object.
4. phase ·add. ·noun a homogenous, physically distinct portion of matter in a system not homogeneous; as, the three phases, ice, water, and aqueous vapor. a phase may be either a single chemical substance or a mixture, as of gases.
5. phase ·noun a particular appearance or state in a regularly recurring cycle of changes with respect to quantity of illumination or form of enlightened disk; as, the phases of the moon or planets. ·see ·illust. under moon.
6. phase ·noun any one point or portion in a recurring series of changes, as in the changes of motion of one of the particles constituting a wave or vibration; one portion of a series of such changes, in distinction from a contrasted portion, as the portion on one side of a position of equilibrium, in contrast with that on the opposite side.
7. phase ·add. ·noun in certain birds and mammals, one of two or more color variations characteristic of the species, but independent of the ordinary seasonal and sexual differences, and often also of age. some of the herons which appear in white and colored phases, and certain squirrels which are sometimes uniformly blackish instead of the usual coloration, furnish examples. color phases occur also in other animals, notably in butterflies.
8. phase ·add. ·noun the relation at any instant of a periodically varying electric magnitude, as electro-motive force, a current, ·etc., to its initial value as expressed in factorial parts of the complete cycle. it is usually expressed in angular measure, the cycle beb four right angles, or 360°. such periodic variations are generally well represented by sine curves; and phase relations are shown by the relative positions of the crests and hollows of such curves. magnitudes which have the same phase are said to be in phase.