[ feyz-in ]

  1. an act or instance of phasing in; gradual introduction or implementation.

Origin of phase-in

Noun use of verb phrase phase in

Words Nearby phase-in Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use phase-in in a sentence

British Dictionary definitions for phase in

phase in

  1. (tr, adverb) to introduce in a gradual or cautious manner: the legislation will be phased in over two years

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

Other Idioms and Phrases with phase-in


Introduce one stage at a time. For example, New technology must be phased in or the office will be overwhelmed. The antonym is phase out, meaning “to bring or come to an end, one stage at a time,” as in The department is phasing out all the older computers. [Mid-1900s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.