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

Meanwhile, the underlying infrastructure—spanning containers, orchestration layers and APIs—must be fortified to withstand new classes of threats. —Anuj Tyagi, Forbes.com, 16 May 2025

These underlying conditions also lead to widespread inflammation in the body, according to Rosenblum. —Kaitlin Sullivan, Health, 16 May 2025

When diagnosing dopamine deficiency, healthcare providers typically focus on the symptoms a person is experiencing to find the underlying cause and address it directly rather than the deficiency itself. —Angelica Bottaro, Verywell Health, 15 May 2025

However, some of the underlying data the framework depends on could become harder to get as the Trump administration seeks to eliminate programs associated with climate change. —Jeff Young, MSNBC Newsweek, 15 May 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