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

But the star of the evening was a brand-new drone show accompanying the fireworks, with 500 colorful drones lighting up in intricate formations. — Camila Pedrosa, Sacbee.com, 4 July 2026

Punctuating the fairly flat state, the Badlands contain rock formations that have resulted from millions of years of deposition and hundreds of thousands of years of erosion. — Josh Laskin, Travel + Leisure, 3 July 2026

The group’s formation is an indication of how the investigation of UAPs and the possibility of contact with intelligent alien life has gained acceptance in mainstream culture—and the halls of power. — Adam Kovac, Scientific American, 2 July 2026

The company said later releases will add non-woven fabric formation, viscose, apparel assembly, bovine leather, and dyeing and printing chemicals. — Roy Stephen Canivel, Footwear News, 2 July 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