from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The satellite of Mars that is second in distance from the planet.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. A son of Ares (Latin: Mars).
- proper n. The outermost natural satellite of Mars.
from The Century Dictionary and Cyclopedia
- n. A satellite of Mars, revolving about its primary in 30 hours and 18 minutes. It was discovered by Asaph Hall, of Washington, in 1877.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the outer of two small satellites of Mars
Greek, one of the sons of Ares, from deimos, fear, terror.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek Δεῖμος (Deimos), from δειμός (deimos, "fear"). (Wiktionary)