The Collaborative International Dictionary of English v.0.48:

Lawsonia \Law*so"ni*a\, n. (Bot.)
   An Asiatic and North African shrub (Lawsonia inermis), with
   smooth oval leaves, and fragrant white flowers. Henna is
   prepared from the leaves and twigs. In England the shrub is
   called Egyptian privet, and in the West Indies, Jamaica
   mignonette.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Privet \Priv"et\, n. [Cf. Scot. privie, Prov. E. prim-print,
   primwort. Prob. for primet, and perh. named from being cut
   and trimmed. See, Prim, a., and cf. Prime to prune,
   Prim, n., Prie, n.] (Bot.)
   An ornamental European shrub (Ligustrum vulgare), much used
   in hedges; -- called also prim.
   [1913 Webster]

   Egyptian privet. See Lawsonia.

   Evergreen privet, a plant of the genus Rhamnus. See
      Alatern.

   Mock privet, any one of several evergreen shrubs of the
      genus Phillyrea. They are from the Mediterranean region,
      and have been much cultivated for hedges and for
      fancifully clipped shrubberies.
      [1913 Webster]