noun

• (astronomy) A particular appearance or state in a regularly recurring cycle of changes with respect to quantity of illumination or form, or the absence, of a body's illuminated disk. Illustrated in Wikipedia's article Lunar phase.
  "the phases of the moon"
• (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.
• (chemistry) A component in a material system that is distinguished by chemical composition and/or physical state (solid, liquid or gas) and/or crystal structure. It is delineated from an adjoining phase by an abrupt change in one or more of those conditions.
• (zoology) In certain organisms, one of two or more colour variations characteristic of the species, but independent of the ordinary seasonal and sexual differences, and often also of age.

verb

• (with in or out) To begin—if construed with "in"—or to discontinue—if construed with out—(doing) something over a period of time (i.e. in phases).
  "The use of the obsolete machines was gradually phased out as the new models were phased in."
• (genetics, informal, transitive) To determine haplotypes in (data) when genotypes are known.
• (science fiction) To use a phaser.

verb

• (proscribed) Alternative spelling of faze

name

• (obsolete) Passover