• synonyms


or phase-out

[ feyz-out ]
/ ˈfeɪzˌaʊt /


an act or instance of phasing out; planned discontinuation or expiration.


Feeling Left Out: Idioms That Hurt LeftiesRead more in this article about some frequently asked questions and fun facts related to our definitions.


cancel, terminate, eliminate

Nearby words

phase-contrast microscope, phase-in, phase-switching, phased array, phasedown, phaseout, phases of matter, phasing, phasis, phasmid, phasor

Origin of phaseout

First recorded in 1955–60; noun use of verb phrase phase out

Definition for phase out (2 of 2)


[ feyz ]
/ feɪz /


verb (used with object), phased, phas·ing.

to schedule or order so as to be available when or as needed.
to put in phase; synchronize: to phase one mechanism with another.

Verb Phrases

Origin of phase

1805–15; (noun) back formation from phases, plural of phasis
Related forms
Can be confusedfaze phase Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for phase out (1 of 2)

phase out


(tr, adverb) to discontinue or withdraw gradually

noun phase-out

the action or an instance of phasing outa phase-out of conventional forces

British Dictionary definitions for phase out (2 of 2)


/ (feɪz) /


verb (tr)

Derived Formsphaseless, adjectivephasic or phaseal, adjective

Word Origin for phase

C19: from New Latin phases, pl of phasis, from Greek: aspect; related to Greek phainein to show
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for phase out


[ fāz ]


A characteristic form, appearance, or stage of development that occurs in a cycle or that distinguishes some individuals of a group.
A discrete homogeneous part of a material system that is mechanically separable from the rest, as is ice from water.
Any of the forms or states, solid, liquid, gas, or plasma, in which matter can exist, depending on temperature and pressure.
A particular stage in a periodic process or phenomenon such as a wave form or time pattern.


To introduce, one stage at a time.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for phase out


[ fāz ]

Any of the forms, recurring in cycles, in which the Moon or a planet appears in the sky.
One of a set of possible homogenous, discrete states of a physical system. States of matter such as solid and liquid are examples of phases, as are different crystal lattice structures in metals such as iron. See also phase transition state of matter.
A measure of how far some cyclic behavior, such as wave motion, has proceeded through its cycle, measured in degrees or radians. At the beginning of the phase, its value is zero; at one quarter of its cycle, its phase is 90 degrees (π/2 radians); halfway through the cycle its value is 180 degrees (π radians), and so on.♦ The phase angle between two waves is a measure of their difference in phase. Two waves of the same frequency that are perfectly in phase have phase angle zero; if one wave is ahead of the other by a quarter cycle, its phase angle 90 degrees (π/2 radians); waves that are perfectly out of phase have phase angle 180 degrees (π radians), and so on. See more at wave.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.