I. ˈhī-drə noun
Etymology: Middle English Ydra, from Latin Hydra, from Greek
Date: 15th century
1. : a many-headed serpent or monster in Greek mythology that was slain by Hercules and each head of which when cut off was replaced by two others
2. not capitalized : a multifarious evil not to be overcome by a single effort
3.
[Latin (genitive Hydrae ), from Greek]
: a southern constellation of great length that lies south of Cancer, Sextans, Corvus, and Virgo and is represented on old maps by a serpent
4. not capitalized
[New Latin, from Latin, Hydra]
: any of numerous small tubular freshwater hydrozoan polyps ( Hydra and related genera) having at one end a mouth surrounded by tentacles
II. ˈhī-drə geographical name
or Modern Greek Ídhra ˈēth-rä
island Greece in S Aegean Sea off E coast of Peloponnese area 20 square miles (52 square kilometers ), population 2794
• Hy·dri·ot ˈhī-drē-ət, -drē-ˌät or Hy·dri·ote -ˌōt, -ət noun