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

Most of the new software underlying AI was developed by small teams with six to eight members. —Patrick Moorhead, Forbes.com, 20 June 2025

Senate Republicans are pitching a smaller increase to the CTC, to $2,200, but the underlying machinery would similarly limit the benefit for the lowest-income households. —Cory Turner, NPR, 20 June 2025

But there is an underlying fear in Geneva that the reinvigorated talks here, the first formal meetings with Iranian representatives since the escalation of the Israel-Iran conflict, will still go nowhere. —Matthew Chance, CNN Money, 20 June 2025

Several chart analysts are confident the stock comeback can continue, given the strength of the underlying market. —Sarah Min, CNBC, 20 June 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