phase

Etymology

From New Latin phasis, from Ancient Greek φάσις (phásis, “an appearance”), from φάω (pháō, “to shine”); compare phantasm and see face.

noun

1. A distinguishable part of a sequence or cycle occurring over time.
2. That which is exhibited to the eye; the appearance which anything manifests, especially any one among different and varying appearances of the same object.
3. Any appearance or aspect of an object of mental apprehension or view.
   The problem has many phases.
4. (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.
   the phases of the moon
5. (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.
6. (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.
7. (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.
8. (rugby union) The period of play between consecutive breakdowns.
   When Romania did manage to string together some phases midway through the first half, England's discipline held firm, although on the whole it was a less focused display from the Six Nations champions in the second half. September 24, 2011, Ben Dirs, “Rugby World Cup 2011: England 67-3 Romania”, in BBC Sport
9. (genetics) A haplotype.
10. (mathematics) The arctangent of the quotient formed by dividing the imaginary part of a complex number by the real part.
11. (music) A distortion caused by a difference in the speed of propagation for different frequencies
12. (electrical engineering) In a polyphase electrical power system, one of the power-carrying conductors, or the alternating current carried by it.

verb

1. (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.
2. Antique form of faze.
3. (genetics, informal, transitive) To determine haplotypes in (data) when genotypes are known.
4. To pass into or through a solid object.
   Anyone who has lost their way in cyberspace—realizing they have just phased into what they had previously categorized as 'solid' matter—will understand this example. 1997, P. Lunenfeld, “Hybrid Architectures and the Paradox of Unfolding”, in Intelligent Environments: Spatial Aspects of the Information Revolution, page 443
   Archer took a deep breath and, steeling himself for the bizarre experience, carefully walked to the bulkhead and phased through. 2004, Paul Ruditis, Star Trek: Enterprise: Shockwave, page 100
   Intangible or invisible objects in comic books are often drawn with a dotted line. When Kitty Pryde of the X-Men phases through objects, she's drawn that way, and Wonder Woman's invisible plan [sic] used to be drawn that way as well. 2011, Timothy Callahan, Grant Morrison: The Early Years, page 93
5. (science fiction) To use a phaser.