1. [n]  (astronomy) the particular appearance of a body's state of illumination (especially one of the recurring shapes of the part of Earth's moon that is illuminated by the sun); "the full phase of the moon"
2. [n]  a particular point in the time of a cycle; measured from some arbitrary zero and expressed as an angle
3. [n]  any distinct time period in a sequence of events; "we are in a transitional stage in which many former ideas must be revised or rejected"
4. [n]  (physical chemistry) a distinct state of matter in a system; matter that is identical in chemical composition and physical state and separated from other material by the phase boundary; "the reaction occurs in the liquid phase of the system"
5. [v]  adjust so as to be in a synchronized condition; "he phased the intake with the output of the machine"
6. [v]  arrange in phases or stages; "phase a withdrawal"

1. \Phase\, n.
   1. (Phys. Chem.) 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.
   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. \Phase\, v. t. [Cf. {Feeze}.]
   To disturb the composure of; to disconcert; to nonplus.
   [Colloq.]
   

3. \Phase\, n.; pl. {Phases}. [NL. phasis, Gr. ?, fr. ? to
   make to appear: cf. F. phase. See {Phenomenon}, {Phantom},
   and {Emphasis}.]
   1. That which is exhibited to the eye; the appearance which
      anything manifests, especially any one among different and
      varying appearances of the same object.
   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.
   

1. The offset of one's waking-sleeping schedule with respect to the standard 24-hour cycle; a useful concept among people who often work at night and/or according to no fixed schedule. It is not uncommon to change one's phase by as much as 6 hours per day on a regular basis. "What's your phase?" "I've been getting in about 8 P.M. lately, but I'm going to wrap around to the day schedule by Friday." A person who is roughly 12 hours out of phase is sometimes said to be in "night mode". (The term "day mode" is also (but less frequently) used, meaning you're working 9 to 5 (or, more likely, 10 to 6).) The act of altering one's cycle is called "changing phase"; "phase shifting" has also been recently reported from Caltech.

2. "change phase the hard way": To stay awake for a very long time in order to get into a different phase.

3. "change phase the easy way": To stay asleep, etc. However, some claim that either staying awake longer or sleeping longer is easy, and that it is *shortening* your day or night that is really hard (see wrap around). The "jet lag" that afflicts travelers who cross many time-zone boundaries may be attributed to two distinct causes: the strain of travel per se, and the strain of changing phase. Hackers who suddenly find that they must change phase drastically in a short period of time, particularly the hard way, experience something very like jet lag without travelling.