- any of various marine gastropods with a low conical shell open beneath, often browsing on rocks at the shoreline and adhering when disturbed.
- any of numerous marine gastropods, such as Patella vulgata (common limpet) and Fissurella (or Diodora) apertura (keyhole limpet), that have a conical shell and are found clinging to rocks
- any of various similar freshwater gastropods, such as Ancylus fluviatilis (river limpet)
- relating to or denoting certain weapons that are attached to their targets by magnetic or adhesive properties and resist removal
- a small open caisson shaped to fit against a dock wall, used mainly in repair work
