- the particular appearance presented by the moon or a planet at a given time.
- one of the recurring appearances or states of the moon or a planet in respect to the form, or the absence, of its illuminated disk: the phases of the moon.
verb (used with object), phased, phas·ing.
Origin of phase
Synonyms for phase
- the fraction of a cycle of a periodic quantity that has been completed at a specific reference time, expressed as an angle
- (as modifier)a phase shift
Word Origin for phase
1705, "phase of the moon," back-formed as a singular from Modern Latin phases, plural of phasis, from Greek phasis "appearance" (of a star), "phase" (of the moon), from stem of phainein "to show, to make appear" (see phantasm). Latin singular phasis was used in English from 1660. Non-lunar application is first attested 1841. Meaning "temporary difficult period" (especially of adolescents) is attested from 1913.
"to synchronize," 1895, from phase (n.). Meaning "to carry out gradually" is from 1949, hence phase in "introduce gradually" (1954), phase out (1954). Related: Phased; phasing.