phase

A distinguishable part of a sequence or cycle occurring over time.

That which is exhibited to the eye; the appearance which anything manifests, especially any one among different and varying appearances of the same object.

Any appearance or aspect of an object of mental apprehension or view.

(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 its enlightened disk. Illustrated in Wikipedia's article Lunar phase.

(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.

(rugby union) The period of play between consecutive breakdowns.

(genetics) A haplotype.

(mathematics) The arctangent of the quotient formed by dividing the imaginary part of a complex number by the real part.

(music) A distortion caused by a difference in the speed of propagation for different frequencies

(electrical engineering) In a polyphase electrical power system, one of the power-carrying conductors, or the alternating current carried by it.