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

But the use of chatbots — the same underlying technology that billions use for mundane tasks like writing emails — is now being used on the battlefield. —Parmy Olson, Mercury News, 7 Mar. 2026

Companies like Strategy further amplify these dynamics by layering leverage on top of already volatile underlying assets. —Mariana Trujillo, Oc Register, 6 Mar. 2026

Not all music needs to have some deep, underlying meaning, and that’s exactly what Spanish artist Bad Gyal believes. —Carly Thomas, HollywoodReporter, 6 Mar. 2026

An underlying benefit Michael Bunting, acquired by DAL, is a middle-six complementary winger who hangs out around the slot grappling for tips and rebounds or getting open for back-door passes. —Sportsday Staff, Dallas Morning News, 5 Mar. 2026

Word History

First Known Use

1611, in the meaning defined at sense 1a

Rhymes for underlying

• amplifying
• beautifying
• certifying
• clarifying
• classifying
• codifying
• crucifying
• edifying
• falsifying
• fortifying
• glorifying
• gratifying

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