The Collaborative International Dictionary of English v.0.48:

Pastel \Pas"tel\, n. [F.; cf. It. pastello. Cf. Pastil.]
   1. A crayon made of a paste composed of a color ground with
      gum water. [Sometimes incorrectly written pastil.]
      "Charming heads in pastel." --W. Black.
      [1913 Webster]

   2. (Bot.) A plant affording a blue dye; the woad (Isatis
      tinctoria); also, the dye itself.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pastil \Pas"til\, Pastille \Pas*tille"\, n. [F. pastille, L.
   pastillusa pastus food. See Pasture, and cf. Pastel.]
   1. (Pharmacy) A small cone or mass made of paste of gum,
      benzoin, cinnamon, and other aromatics, -- used for
      fumigating or scenting the air of a room.
      [1913 Webster]

   2. An aromatic or medicated lozenge, especially one used to
      soothe a sore throat; a troche. [WordNet sense 1]

   Syn: cough drop, troche.
        [1913 Webster]

   3. See Pastel, a crayon.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pastil
    n 1: a medicated lozenge used to soothe the throat [syn: cough
         drop, troche, pastille, pastil]