Source : Webster's Revised Unabridged Dictionary (1913)

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.

   2. (Bot.) A plant affording a blue dye; the woad ({Isatis
      tinctoria}); also, the dye itself.

Source : WordNet®

pastel
     adj 1: lacking in body or vigor; "faded pastel charms of the naive
            music"
     2: delicate and pale in color; "pastel pink"

pastel
     n : any of various pale or light colors