from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A small, brightly colored live-bearing freshwater fish (Poecilia reticulata or Lebistes reticulatus), native to northern South America and adjacent islands of the West Indies and popular in home aquariums.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A tiny freshwater fish, Poecilia reticulata, popular in home aquariums, that usually has a plain body and black or dark blue tail for the females and a more colorful tail for the males.
- n. By extension, any tiny fish.
from the GNU version of the Collaborative International Dictionary of English
- n. A small freshwater fish of South America and West Indies (Lebistes reticulatus or Poecilia reticulata, originaly called Gerardinus guppyi), often kept in aquariums; also called rainbow fish.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. small freshwater fish of South America and the West Indies; often kept in aquariums
After R.J. Lechmere Guppy (1836-1916), clergyman of Trinidad who first supplied specimens to the British Museum.(American Heritage® Dictionary of the English Language, Fourth Edition)
From a name mistakenly assigned, Girardinus guppii, after biologist Robert J. L. Guppy, to previously assigned Poecilia reticulata (Wiktionary)