Mermaid fish

from The Collaborative International Dictionary of English v.0.48
Mermaid \Mer"maid\, n. [AS. mere lake, sea. See {Mere} lake, and
   {maid}.]
   A fabled marine creature, typically represented as having the
   upper part like that of a woman, and the lower like a fish; a
   sea nymph, sea woman, or woman fish.
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   Note: Chaucer uses this word as equivalent to the siren of
         the ancients.
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   {Mermaid fish} (Zool.) the angel fish ({Squatina}).

   {Mermaid's glove} (Zool.), a British branched sponge somewhat
      resembling a glove.

   {Mermaid's head} (Zool.), a European spatangoid sea urchin
      ({Echinocardium cordatum}) having some resemblance to a
      skull.

   {Mermaid weed} (Bot.), an aquatic herb with dentate or
      pectinate leaves ({Proserpinaca palustris} and
      {Proserpinaca pectinacea}).
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