ac·​cre·​tion | \ ə-ˈkrē-shən How to pronounce accretion (audio) \

Definition of accretion

1 : the process of growth or enlargement by a gradual buildup: such as
a : increase by external addition or accumulation (as by adhesion of external parts or particles)
b : the increase of land by the action of natural forces
2 : a product of accretion especially : an extraneous addition accretions of grime

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Other Words from accretion

accretionary \ ə-​ˈkrē-​shə-​ˌner-​ē How to pronounce accretion (audio) , -​ˌne-​rē \ adjective

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The slow accretion of scientific knowledge over many centuries has turned into an avalanche in our time. Any accretion of ice on a grounded jet will result in takeoff delays because of the danger it poses. The land area of the Mississippi Delta increases every year from the accretion of soil washed down the Mississippi River, though the accretions happen so slowly that it's difficult to detect any increase at all. Accretion is often used in scientific writing; its usual verb form, accrue, is more often used in financial contexts ("This figure doesn't count the accrued interest on the investments").

Examples of accretion in a Sentence

rocks formed by the slow accretion of limestone There was an accretion of ice on the car's windshield.
Recent Examples on the Web Yet the accretion of little gestures—hands thrust in and out of pockets, gazes redirected—is one of Rooney’s sharpest distinctions as a stylist. Lauren Michele Jackson, The New Yorker, 10 Sep. 2021 Opatrný says using the radiation from accretion disks would be particularly clever, because the disks convert energy more efficiently than the thermonuclear reaction in conventional stars. Ian Randall, Science | AAAS, 16 Aug. 2021 One airline, a MetricSream customer, is empowering its frontline workers through mobile apps that make automated updates and real-time communications that compress the timeline for turnaround and ultimately solve for revenue accretion. Gaurav Kapoor, Forbes, 6 July 2021 New ideas did not arrive magically from inspiration but were instead wrought from preexisting ideas, in new combinations, and in the slow accretion of existing material that would occasionally burst forth into something new and striking. Colin Dickey, The New Republic, 21 July 2021 Its hallmark is an accretion of amyloid plaque and tau tangles in the brain, which usually begins long before people show symptoms. The Editorial Board, WSJ, 7 June 2021 At first, in the ’80s, researchers magnetized the accretion disks in their simulations just a little. Quanta Magazine, 20 May 2021 The major alternative to monolithic collapse, this scenario conjectures that most of the early galaxies that form are small, spiral-like, and grow by accretion and mergers. Ethan Siegel, Forbes, 11 May 2021 The story of American finance in the past 100 years is the story of the accretion of government power over money and banking and the reciprocal loss of individual responsibility for profit and loss. James Grant, WSJ, 7 May 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'accretion.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of accretion

1615, in the meaning defined at sense 1

History and Etymology for accretion

borrowed from Latin accrētiōn-, accrētiō "increase," from accrē- (stem of accrēscere "to increase, be added") + -tiōn-, -tiō, suffix of action nouns — more at accrue

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The first known use of accretion was in 1615

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Last Updated

10 Oct 2021

Cite this Entry

“Accretion.” Dictionary, Merriam-Webster, Accessed 24 Oct. 2021.

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More Definitions for accretion



English Language Learners Definition of accretion

: a gradual process in which layers of a material are formed as small amounts are added over time
: something that has grown or accumulated slowly : a product or result of gradual growth


ac·​cre·​tion | \ ə-ˈkrē-shən How to pronounce accretion (audio) \

Medical Definition of accretion

: the process of growth or enlargement especially : increase by external addition or accumulation (as by adhesion of external parts or particles) — compare apposition sense 1, intussusception sense 2

Other Words from accretion

accretionary \ -​shə-​ˌner-​ē How to pronounce accretion (audio) \ adjective


ac·​cre·​tion | \ ə-ˈkrē-shən How to pronounce accretion (audio) \

Legal Definition of accretion

1 : the process or a result of growth or enlargement: as
a : the increase or extension of the boundaries of land or the consequent acquisition of land accruing to the owner by the gradual or imperceptible action of natural forces (as by the washing up of sand or soil from the sea or a river or by a gradual recession of the water from the usual watermark) also : accession in which the boundaries of land are enlarged by this process — compare avulsion, reliction
b : increase in the amount or extent of any kind of property or in the value of any property accretions to a trust fund resulting from the increase in value of…securities in which its corpus is investedIn re Estate of Gartenlaub, 244 P. 348 (1926)

Note: Accretion in value of the principal of a trust is generally not considered income.

c : enlargement of a bargaining unit by the addition of new employees
2 in the civil law of Louisiana : the passing to an heir or conjoint legatee of the right to accept a portion of a succession resulting from the failure of a coheir or colegatee to take his or her own share

More from Merriam-Webster on accretion

Nglish: Translation of accretion for Spanish Speakers

Britannica English: Translation of accretion for Arabic Speakers Encyclopedia article about accretion


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