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Earth Day

American  
[urth dey] / ˈɜrθ ˌdeɪ /

noun

  1. April 22, a day set aside globally for raising awareness about environmental issues and participating in events to help protect the environment.

Etymology

Origin of Earth Day

First recorded in 1970

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The environmental group has been conducting habitat restoration in the reserve since 2019, with this weekend’s event also a late celebration of Earth Day, after a prior event was rained out.

From Los Angeles Times • May 25, 2025

Though much has changed over the last five decades, this year’s Earth Day holds particular meaning in eco-conscious California.

From Los Angeles Times • Apr. 22, 2025

Just in time for National Parks Week and Earth Day, no less.

From Slate • Apr. 22, 2025

No wonder, then, that Americans planned nationwide Earth Day protests.

From Slate • Apr. 22, 2025

Meggers’s message of limitation, published within a year of the first Earth Day, resonated in the ears of readers newly converted to the ecological movement.

From "1491" by Charles C. Mann

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.