petra — an ancient Arab kingdom of SW Asia, in the area of present-day Jordan, that became a Roman province in a.d. 106. Capital: Petra.
tetra — any of several tropical, freshwater fishes of the family Characidae, often kept in aquariums.
Four-or-more syllable rhymes
cardinal tetra — a small, brilliantly colored red and blue characin fish, Paracheirodon axelrodi, native to tropical forest streams in Brazil and Colombia: a popular aquarium fish.
