underlying

adjective

un·​der·​ly·​ing ˌən-dər-ˈlī-iŋ 

1

a

: lying beneath or below

the underlying rock is shale

b

: basic, fundamental

an investigation of the underlying issues

2

: evident only on close inspection : implicit

3

: anterior and prior in claim

underlying mortgage

4

: of or being present in deep structure

underlying word order

Synonyms of underlying

• basic
• rudimentary
• elementary
• fundamental
• introductory

Examples of underlying in a Sentence

the ocean and the underlying rock

the underlying differences between democracy and dictatorship

Recent Examples on the Web

Although bilateral engagement expanded, underlying tensions continued to surface throughout the period. — Encyclopedia Britannica, 22 July 2026

Battery manufacturing, solar, wind and hydrogen each have distinct value chains, but many of the underlying competencies overlap. — Elena Bou, Forbes.com, 22 July 2026

Analysts pointed to its forecast for an underlying measure of revenue growth for the summer, which was weaker than Wall Street expected. — ABC News, 21 July 2026

The chip would work with future Gemini models only if Google sticks with the same underlying architecture, according to The Information. — Mackenzie Sigalos, CNBC, 20 July 2026

Word History

First Known Use

1611, in the meaning defined at sense 1a

Rhymes for underlying

• applying
• belying
• complying
• decrying
• defying
• denying
• implying
• outlying
• relying
• replying
• supplying
• undying

Kids Definition

underlying

adjective

un·​der·​ly·​ing ˌən-dər-ˌlī-iŋ 

1

: lying under or below

the underlying rock

2

: fundamental entry 1 sense 1

Medical Definition

underlying

adjective

un·​der·​ly·​ing -ˌlī-iŋ 

: serving as a basis or cause (as of secondary symptoms)

the underlying brain malformation that caused the hydrocephalus

—R. M. Henig