Deimos

American

[dahy-mos] / ˈdaɪ mɒs /

noun

an ancient Greek personification of terror, a son of Ares and Aphrodite.
Astronomy. one of the two moons of Mars.

Deimos British

/ ˈdeɪmɒs /

noun

the smaller of the two satellites of Mars and the more distant from the planet. Approximate diameter: 13 km Compare Phobos

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Deimos Scientific

/ dē′mōs,dā′- /

The satellite of Mars that is second in distance from the planet.

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.

Researchers believe micrometeorites striking Mars' moons, Phobos and Deimos, may throw dust particles into space.

From Science Daily • May 11, 2026

Recently it captured high-resolution images of Deimos, the smaller of the two Martian moons.

From New York Times • May 29, 2023

Deimos, at more than 23,000 km in altitude, takes slightly more than 30 hours to orbit.

From Scientific American • May 2, 2023

Of course, as The New York Times reported, it is not yet clear with any certainty how Deimos was formed from Mars.

From Salon • Apr. 28, 2023

The information I have suggests that Deimos and Phobos look somewhat similar to Earth’s moon, though they are much smaller in size.

From "A Rover's Story" by Jasmine Warga

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