underpinning

noun

un·​der·​pin·​ning ˈən-dər-ˌpi-niŋ 

1

: the material and construction (such as a foundation) used for support of a structure

2

: something that serves as a foundation : basis, support

—often used in plural

the philosophical underpinnings of educational methods

3

: underwear

—usually used in plural

4

: a person's legs

—usually used in plural

Synonyms

• basis
• foundation
• bedrock
• cornerstone

Examples of underpinning in a Sentence

the underpinnings of the theory have recently been called into question

the underpinnings of the bridge were seriously damaged in the collision

Recent Examples on the Web

Also to folks that say, technology does not matter, business use cases over technology seem unaware of the fact that basic capabilities baked into the technical underpinnings are needed BEFORE any business use cases can come to fruition. —Vipin Bharathan, Forbes.com, 24 July 2025

The Truman vision—the world as orchestra, the U.S. President as conductor—may have run its course, though; its economic underpinnings are eroding and its political costs are mounting. —Daniel Immerwahr, New Yorker, 16 June 2025

Toyota Sequoia: Interior Space Reduced Despite its body-on-frame underpinnings, the 2025 Toyota Sequoia delivers confident handling and a refined ride quality. —Karl Brauer, Forbes.com, 7 July 2025

Appreciate Wilson’s technical brilliance but also the emotional generosity of his choral arrangements in which falsetto yearning is granted bass underpinning. —Armond White, National Review, 18 June 2025

Word History

First Known Use

15th century, in the meaning defined at sense 1

Rhymes for underpinning

• beginning
• binning
• dinning
• ginning
• grinning
• inning
• pinning
• sinning
• skinning
• spinning
• thinning
• tinning

Kids Definition

underpinning

noun

un·​der·​pin·​ning ˈən-dər-ˌpin-iŋ 

1

: the foundation used for support of a structure

2

: prop entry 1, support

3

: a person's legs

—usually used in plural