formation

noun

for·​ma·​tion fȯr-ˈmā-shən 

1

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

2

: something that is formed

new word formations

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

• 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

But Flacco was unable to find Andre Iosivas twice on third- and fourth-and-9 to turn the ball over on downs and give the Jets their first victory formation of the year. —Scott Thompson, FOXNews.com, 26 Oct. 2025

This robust interface, enriched with lithium fluoride and lithium nitride, effectively suppresses dendrite formation. —Aman Tripathi, Interesting Engineering, 26 Oct. 2025

In the years leading up to the formation of the Wood Brothers, Oliver and Chris had been living apart, each wandering their own respective paths from both sides of the Mason-Dixon Line. —Garret K. Woodward, Rolling Stone, 26 Oct. 2025

At the same time, gluten formation when the dough is mixed helps create the strength needed to trap those air pockets. —Katie Rosenhouse, Southern Living, 26 Oct. 2025

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