formation

noun

for·​ma·​tion fȯr-ˈmā-shən 

1

: an act of giving form or shape to something or of taking form : development

the formation of the planets

2

: something that is formed

new word formations

a rock formation

3

: the manner in which a thing is formed : structure

the peculiar formation of the heart

4

: a major kind of plant growth (such as forest, grassland, or tundra) characteristic of a broad ecological region

5

a

: any igneous, sedimentary, or metamorphic rock represented as a unit

b

: any sedimentary bed or consecutive series of beds sufficiently homogeneous or distinctive to be a unit

6

: an arrangement of a body or group of persons or things in some prescribed manner or for a particular purpose

flying in formation

Synonyms of formation

• layout
• format

Examples of formation in a Sentence

The book explains the formation of the planets.

The soldiers were marching in formation.

The team ran on the field and lined up in a punt formation.

Recent Examples on the Web

Rather than heading straight for Utah, spend time exploring the desert beyond the Strip, including the red-rock formations and ancient petroglyphs of Valley of Fire State Park. — Lauren Dana Ellman, Travel + Leisure, 24 Sep. 2026

By next year, Google is hoping to launch another pair of satellites before ramping up to a constellation of 80 satellites in close formation. — Victor Tangermann, Futurism, 24 Sep. 2026

That means no matter the scale of the black hole, a few times the mass of the sun or a billion, jet formation is the same across black holes. — Robert Lea, Space.com, 24 Sep. 2026

So far the hurricane season has yet to produce an actual hurricane, though, but has seen the formation of tropical storms Arthur, Bertha, Cristobal, Dolly and Edouard. — Richard Tribou, The Orlando Sentinel, 24 Sep. 2026

Word History

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing formation

• back-formation
• break formation
• I formation
• punt formation
• reticular formation
• self-formation
• spread formation
• T formation

Rhymes for formation

• ablation
• aeration
• bination
• carnation
• cassation
• castration
• causation
• centration
• cessation
• cetacean
• chelation
• citation

Kids Definition

formation

noun

for·​ma·​tion fȯr-ˈmā-shən 

1

: a forming of something

2

: something formed

3

: the manner in which a thing is formed : structure, shape

4

: a bed of rocks or series of beds recognizable as a unit

5

: an arrangement or grouping of persons, ships, or airplanes

Medical Definition

formation

noun

for·​ma·​tion fȯr-ˈmā-shən 

1

: an act of giving form or shape to something or of taking form : development

2

: the manner in which a thing is formed : structure