1. A jellyfish or other gelatinous marine animal of the phylum Cnidaria.
Usage: scientific or formal; plural: acalephes or acalephs

Examples

• The acaleph drifted through the ocean currents with its tentacles trailing behind.
• Marine biologists studied the acaleph's bioluminescent properties in the deep sea.
• An acaleph can deliver a painful sting to swimmers who brush against it.
• The aquarium's collection included several species of acaleph from different ocean depths.