A swarm, bunch, or large group of animals or things in confused or disorderly motion; particularly used for a group of jellyfish.
Irish Gaelic origin, 'flúthraigh' (swarm, flutter). Brought into English through Irish English dialects, particularly in reference to sea creatures and insects in collective groups.
A group of jellyfish is called a 'fluther'—one of the most poetic collective nouns in English, probably because it captures their ghostly, fluttering mass floating together in the ocean.
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