accretion

[ uh-kree-shuhn ]

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.

accretion

/ 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

accretion

/ 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.

Derived Forms

• acˈcretive, adjective

Other Words From

• ac·cre·tive ac·cre·tion·ar·y adjective
• non·ac·cre·tion noun

Word History and Origins

Origin of accretion¹

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

Word History and Origins

Origin of accretion¹

C17: from Latin accretiō increase, from accrēscere. See accrue

Example Sentences

A 2023 study in The Astrophysical Journal revealed that black holes which suck up gases — forming what's known as accretion disks — do so in a manner of mere months, which is extremely rapid on an interstellar timescale, as well as 10 to 100 times faster than scientists previously believed.

From Salon

The researchers led by Northwestern University's Nick Kaaz, a graduate student in astronomy, used computer simulations to determine that the black hole causes rotations which warp the accretion disk in such a way that the gas actually starts caving in on itself.

From Salon

Eventually the entire accretion disk is torn in half, with the black hole first consuming the inner disc and then the outer one.

From Salon

They can consume gas from their host galaxies in a process called accretion, and they can also merge with each other when two galaxies collide.

From Salon

When there isn’t enough gas available for supermassive black holes to grow by accretion, the only way for them to get larger is through mergers.

From Salon

Related Words

• accumulation