What does the word limpet mean?

Usage examples for limpet

  1. He managed to pull him out, and when he had him safe and breathless on shore, he saw that the boat was nearing the ship, and that Date, torn and wet and disheveled, with three policemen, was up to his waist in water, struggling to bring ashore Cockatoo and the mummy case, to which he clung like a limpet. – The Green Mummy by Fergus Hume
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