accretion

American  

[uh-kree-shuhn] / əˈkri ʃən /

noun

1. an increase by natural growth or by gradual external addition; growth in size or extent.

2. the result of this process.

3. an added part; addition.

   The last part of the legend is a later accretion.

4. the growing together of separate parts into a single whole.

5. Law. increase of property by gradual natural additions, as of land by alluvion.

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accretion British  

/ əˈkriːʃən /

noun

1. any gradual increase in size, as through growth or external addition

2. something added, esp extraneously, to cause growth or an increase in size

3. the growing together of normally separate plant or animal parts

4. pathol

   1. abnormal union or growing together of parts; adhesion

   2. a mass of foreign matter collected in a cavity

5. law an increase in the share of a beneficiary in an estate, as when a co-beneficiary fails to take his share

6. astronomy the process in which matter under the influence of gravity is attracted to and increases the mass of a celestial body. The matter usually forms an accretion disc around the accreting object

7. geology the process in which a continent is enlarged by the tectonic movement and deformation of the earth's crust

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accretion Scientific  

/ ə-krē′shən /

1. Geology The gradual extension of land by natural forces, as in the addition of sand to a beach by ocean currents, or the extension of a floodplain through the deposition of sediments by repeated flooding.

2. Astronomy The accumulation of additional mass in a celestial object by the drawing together of interstellar gas and surrounding objects by gravity.

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Other Word Forms

• accretionary adjective
• accretive adjective
• nonaccretion noun

Etymology

Origin of accretion

First recorded in 1605–15; from Latin accrētiōn- (stem of accrētiō ), equivalent to accrēt(us), past participle of accrēscere “to grow” ( ac- prefix meaning “toward” + crē- “grow” + -tus past participle suffix) + -iōn- noun suffix; ac-, -ion

Example Sentences

While a partnership with one of the foremost AI developers would be “a vital long-term strategic move against AI search cannibalization,” the price action Thursday overestimates near-term accretion, Reese asserted.

From Barron's • Mar. 6, 2026

But the monarchy is about continuity; it is an accretion of what has come before as well as a living thing that responds to the present.

From BBC • Feb. 19, 2026

In these environments, black holes experienced brief but intense growth spurts through a process known as 'super Eddington accretion'.

From Science Daily • Jan. 26, 2026

But for SGH, “we find accretion and leverage outcomes relatively resilient to changes in bid prices owing to solid deal multiple arbitrage,” they say.

From The Wall Street Journal • Jan. 8, 2026

The actual particulars of the event are unclear, obscured by the accretion of myth.

From "Into Thin Air" by Jon Krakauer

Related Words

• accumulation