The Collaborative International Dictionary of English v.0.48:

Mignonette \Mi`gnon*ette"\, n. [F. mignonnette, dim. of mignon
   darling. See 2d Minion.] (Bot.)
   A plant (Reseda odorata) having greenish flowers with
   orange-colored stamens, and exhaling a delicious fragrance.
   In Africa it is a low shrub, but further north it is usually
   an annual herb.
   [1913 Webster]

   Mignonette pepper, coarse pepper.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mignonette
    n 1: Mediterranean woody annual widely cultivated for its dense
         terminal spikelike clusters greenish or yellowish white
         flowers having an intense spicy fragrance [syn:
         mignonette, sweet reseda, Reseda odorata]