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

Any designer or architect worth their salt will tell you that having an inspired client, wholly engaged in the conceptual and aesthetic underpinnings of a commission, is an enormous boon to the prospect of original creative expression. —Mayer Rus, Architectural Digest, 30 June 2025

Taking a look at the underpinnings, the 6.3-kWh three-battery version of the E-VO weighs 344 lb (156 kg), while the two-battery version weighs 315 lb (143 kg). —Utkarsh Sood june 29, New Atlas, 29 June 2025

But for now, at least, the financial underpinnings of the U.S. economy haven’t suffered damage. —Erik Sherman, Forbes.com, 23 June 2025

Yet despite the ominous underpinning, people were determined to be festive, upbeat. —Howard Blume, Los Angeles Times, 13 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