The Collaborative International Dictionary of English v.0.48:

Sericeous \Se*ri"ceous\, a. [L. sericus silken, sericum Seric
   stuff, silk, fr. Sericus belonging to the Seres, Gr. ???, a
   people of Eastern Asia, the modern Chinese, celebrated for
   their silken fabrics. Cf. Silk, Serge a woolen stuff.]
   1. Of or pertaining to silk; consisting of silk; silky.
      [1913 Webster]

   2. (Bot.) Covered with very soft hairs pressed close to the
      surface; as, a sericeous leaf.
      [1913 Webster]

   3. (Zool.) Having a silklike luster, usually due to fine,
      close hairs.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sericeous
    adj 1: covered with fine soft hairs or down; "downy milkweed
           seeds" [syn: downy, pubescent, puberulent,
           sericeous]