2. (Zo["o]l.) 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.
3. (Elec.) 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[deg]. 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.
2. Any appearance or aspect of an object of mental
apprehension or view; as, the problem has many phases.
3. (Astron.) 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}.
4. (Physics) 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.