blood moon

American

[bluhd moon] / ˈblʌd ˌmun /

noun

a total lunar eclipse, during which a small amount of the sun’s light is refracted through the earth’s atmosphere, causing the blue wavelengths to scatter and allowing more of the red wavelengths to reach the moon.

Etymology

Origin of blood moon

First recorded in 1870–75

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.

People sometimes refer to a lunar eclipse as a "blood moon" because of the way the Moon can turn a deep, coppery red during the eclipse.

From BBC • Mar. 11, 2025

The closer the moon is to the Earth during an eclipse, the redder it looks, making it a super blood moon.

From Slate • Apr. 5, 2024

The coppery, reddish hue caused by an eclipse leads to the name blood moon, seen here in Temple City, Calif.

From New York Times • May 15, 2022

It will be the first so-called blood moon in a year.

From Seattle Times • May 13, 2022

Some of the sails bore devices from the other islands; the blood moon of Wynch, Lord Goodbrother's banded black warhom, Harlaw's silver scythe.

From "A Clash of Kings" by George R.R. Martin

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