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

This work has transformed many fields, including medicine, biology, ecology and forensics, and means that doctors can understand the genetic underpinning of disease more easily, leading to personalized medicine and other treatments, Pendlebury said. —Katie Hunt, CNN Money, 4 Oct. 2025

There’s always been an underpinning of organic modernism and neo primitivism in their work that is a great pairing with the Loewe DNA. —Alex Wynne, Footwear News, 3 Oct. 2025

The unibody structure and assembly were essentially British, with mechanical underpinnings from Volvo’s Amazon/122 series. —Robert Ross, Robb Report, 3 Oct. 2025

Certain other kinds—like ovarian, endometrial, and even pancreatic, stomach, and melanoma—can share genetic underpinnings with breast cancer, so having these in your bloodline could up your risk. —Erica Sloan, SELF, 1 Oct. 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