The Collaborative International Dictionary of English v.0.48:

Violet \Vi"o*let\, n. [F. violette a violet (cf. violet
   violet-colored), dim. of OF. viole a violet, L. viola; akin
   to Gr. ?. Cf. Iodine.]
   1. (Bot.) Any plant or flower of the genus Viola, of many
      species. The violets are generally low, herbaceous plants,
      and the flowers of many of the species are blue, while
      others are white or yellow, or of several colors, as the
      pansy (Viola tricolor).
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   Note: The cultivated sweet violet is Viola odorata of
         Europe. The common blue violet of the eastern United
         States is Viola cucullata; the sand, or bird-foot,
         violet is Viola pedata.
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   2. The color of a violet, or that part of the spectrum
      farthest from red. It is the most refrangible part of the
      spectrum.
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   3. In art, a color produced by a combination of red and blue
      in equal proportions; a bluish purple color. --Mollett.
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   4. (Zool.) Any one of numerous species of small
      violet-colored butterflies belonging to Lycaena, or
      Rusticus, and allied genera.
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   Corn violet. See under Corn.

   Dame's violet. (Bot.) See Damewort.

   Dogtooth violet. (Bot.) See under Dogtooth.

   Water violet (Bot.), an aquatic European herb (Hottonia
      palustris) with pale purplish flowers and pinnatifid
      leaves.
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The Collaborative International Dictionary of English v.0.48:

Dogtooth \Dog"tooth`\, n.; pl. Dogteeth.
   1. See Canine tooth, under Canine.
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   2. (Arch.) An ornament common in Gothic architecture,
      consisting of pointed projections resembling teeth; --
      also called tooth ornament.
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   Dogtooth spar (Min.), a variety of calcite, in acute
      crystals, resembling the tooth of a dog. See Calcite.

   Dogtooth violet (Bot.), a small, bulbous herb of the Lily
      family (genus Erythronium). It has two shining flat
      leaves and commonly one large flower. [Written also
      dog's-tooth violet.]
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WordNet (r) 3.0 (2006):

dogtooth violet
    n 1: perennial woodland spring-flowering plant; widely
         cultivated [syn: dogtooth violet, dogtooth,
         dog's-tooth violet]