Source : Webster's Revised Unabridged Dictionary (1913)

Water plantain \Wa"ter plan"tain\ (Bot.)
   A kind of plant with acrid leaves. See under 2d {Plantain}.

Plantain \Plan"tain\, n. [F., fr. L. plantago. Cf. {Plant}.]
   (Bot.)
   Any plant of the genus {Plantago}, but especially the {P.
   major}, a low herb with broad spreading radical leaves, and
   slender spikes of minute flowers. It is a native of Europe,
   but now found near the abode of civilized man in nearly all
   parts of the world.

   {Indian plantain}. (Bot.) See under {Indian}.

   {Mud plantain}, a homely North American aquatic plant
      ({Heteranthera reniformis}), having broad, reniform
      leaves.

   {Rattlesnake plantain}, an orchidaceous plant ({Goodyera
      pubescens}), with the leaves blotched and spotted with
      white.

   {Ribwort plantain}. See {Ribwort}.

   {Robin's plantain}, the {Erigeron bellidifolium}, a common
      daisylike plant of North America.

   {Water plantain}, a plant of the genus {Alisma}, having acrid
      leaves, and formerly regarded as a specific against
      hydrophobia. --Loudon.

Source : WordNet®

water plantain
     n : marsh plant having clusters of small white or pinkish
         flowers and broad pointed or rounded leaves [syn: {Alisma
         plantago-aquatica}]