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
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
The term reflects a particular cultural formation, dominant in the United States and Israel, but not in Eastern Europe or the former Soviet Union.
—
Literary Hub, 13 Feb. 2026
At the time of formation, no homes were built within the district’s jigsaw boundaries, so no homeowners were around to vote on long-term costs.
—Mark Dee, Idaho Statesman, 13 Feb. 2026
The disease begins with the formation of benign polyps in the body's large intestine, also known as the colon.
—Alyssa Goldberg, USA Today, 12 Feb. 2026
This geological anomaly led to the formation of rare minerals high in sodium and iron — such as arfvedsonite, aegirine and aenigmatite — that typically do not occur in granite.
—Asuka Koda, CNN Money, 11 Feb. 2026
See All Example Sentences for formation
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Literary Hub, 13 Feb. 2026
At the time of formation, no homes were built within the district’s jigsaw boundaries, so no homeowners were around to vote on long-term costs.
—Mark Dee, Idaho Statesman, 13 Feb. 2026
The disease begins with the formation of benign polyps in the body's large intestine, also known as the colon.
—Alyssa Goldberg, USA Today, 12 Feb. 2026
This geological anomaly led to the formation of rare minerals high in sodium and iron — such as arfvedsonite, aegirine and aenigmatite — that typically do not occur in granite.
—Asuka Koda, CNN Money, 11 Feb. 2026
See All Example Sentences for formation
Cite this Entry
“Formation.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/formation. Accessed 15 Feb. 2026.
Copy CitationKids Definition
formation
noun
for·ma·tion
fȯr-ˈmā-shən
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
Love words? Need even more definitions?
Merriam-Webster unabridged
