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

One Baha’i tenet, that the soul begins with the formation of the embryo, led to controversy. —Hillel Italie, Chicago Tribune, 27 Mar. 2026

The natural selection leading to the formation of stronger embryos after short microgravity exposures, on the other hand, could lead to advances in human IVF technologies that help treat infertility on Earth. —Tereza Pultarova, Space.com, 27 Mar. 2026

Atten Hill is a good example of how Crescent thinks about real estate development overall, said Christopher Goff, senior managing director and head of capital formation at Crescent. —Neal Franklin, Dallas Morning News, 27 Mar. 2026

Way back in 2018, Gaines and Riley were running split-back formations and leaving opposing defenses bamboozled while playing for the 12-and-under Moreno Valley Falcons in the heart of Southern California. —Shaun Goodwin, Idaho Statesman, 27 Mar. 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
• bination
• carnation
• cassation
• castration
• causation
• centration
• cessation
• cetacean
• chelation
• citation
• collation

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