noun

1. any of the recurrent stages of variation in the illumination and apparent shape of a moon or a planet
2. any of the stages or forms in any series or cycle of changes, as in development
3. any of the ways in which something may be observed, considered, or presented; aspect; side; part a problem with many phases
4. Chem. a solid, liquid, or gaseous homogeneous form existing as a distinct part in a heterogeneous system ice is a phase of HO
5. Physics the fractional part of a cycle through which an oscillation, as of light or sound waves, has advanced, measured from an arbitrary starting point
6. Zool. any of the characteristic variations in color of the skin, fur, plumage, etc. of an animal, according to season, age, etc.

Etymology: ModL phasis < Gr < phainesthai, to appear, akin to phainein: see fantasy

transitive verb phased, phasing phas′·ing

1. to plan, introduce, or carry out in phases, or stages: often with in or into
2. to put in phase

intransitive verb

transitive verb phased, phasing phas′·ing