1. Plural of hydra; small freshwater organisms with tentacle-like appendages, used in biological research.
Usage: biology; scientific
2. Plural of hydra; in mythology, a many-headed serpent or monster, especially the Hydra of Lerna.
Usage: mythology; classical
3. Plural of hydra; a persistent or multifaceted problem that is difficult to solve.
Usage: figurative

Examples

• Scientists observed the hydrae under the microscope to study their regenerative abilities.
• In ancient Greek mythology, Hercules defeated the Hydra by cutting off its multiple heads.
• The organization faced a hydra of interconnected issues that required careful management.
• Hydrae are commonly used in developmental biology experiments.
• The legend of the Hydra inspired countless artistic depictions throughout history.