Source : Webster's Revised Unabridged Dictionary (1913)

Zinnia \Zin"ni*a\, n. [NL. So called after Professor Zinn, of
   G["o]ttingen.] (Bot.)
   Any plant of the composite genus {Zinnia}, Mexican herbs with
   opposite leaves and large gay-colored blossoms. {Zinnia
   elegans} is the commonest species in cultivation.

Zinnia \Zin"ni*a\, n. [NL. So called after Professor Zinn, of
   G["o]ttingen.] (Bot.)
   Any plant of the composite genus {Zinnia}, Mexican herbs with
   opposite leaves and large gay-colored blossoms. {Zinnia
   elegans} is the commonest species in cultivation.

Source : WordNet®

zinnia
     n : any of various plants of the genus Zinnia cultivated for
         their variously and brightly colored flower heads [syn: {old
         maid}, {old maid flower}]