underlie

verb

un·​der·​lie ˌən-dər-ˈlī 

underlay ˌən-dər-ˈlā  ; underlain ˌən-dər-ˈlān  ; underlying ˌən-dər-ˈlī-iŋ 

transitive verb

1

: to lie or be situated under

2

: to be at the basis of : form the foundation of : support

ideas underlying the revolution

3

: to exist as a claim or security superior and prior to (another)

4

archaic : to be subject or amenable to

Examples of underlie in a Sentence

A tile floor underlies the rug.

The river is underlain by limestone.

We discussed the principles that underlay their methods.

A theme of revenge underlies much of her writing.

Recent Examples on the Web

This type is directly caused by an underlying health condition, like kidney disease or sleep apnea, or taking medications, like certain painkillers or birth control pills. —Colleen Doherty, Verywell Health, 18 Dec. 2025

Circuit Judge Mavel Ruiz made two rulings Thursday, one lifting a temporary block on the college from transferring the land and a second tossing the underlying public transparency case. —Claire Heddles, Miami Herald, 18 Dec. 2025

The system interprets the vision—described in plain words—and builds the underlying logic, connects payment gateways(coming soon in 2026 Jan), and launches the product. —New Atlas, 17 Dec. 2025

Employment data released this week showing underlying weakness in America’s jobs market may be the foundation for new interest rate cuts from the Fed early next year, according to UBS. —Eleanor Pringle, Fortune, 17 Dec. 2025

Word History

First Known Use

before the 12th century, in the meaning defined at sense 4

Rhymes for underlie

• apply
• awry
• belie
• bely
• bigeye
• bonsai
• buckeye
• comply
• coxae
• decry
• defy
• deny

Kids Definition

underlie

verb

un·​der·​lie ˌən-dər-ˈlī 

underlay -ˈlā  ; underlain -ˈlān  ; underlying -ˈlī-iŋ 

1

: to lie or be located under

2

: to form the foundation of : support

ideas underlying the revolt