The Collaborative International Dictionary of English v.0.48:

Indument \In"du*ment\, n. [L. indumentum a covering. See
   Indue, and cf. Induement.]
   1. (Zool.) Plumage; feathers.
      [1913 Webster]

   2. (Bot., Zool.) A dense covering, especially a hairy one;
      called also indumentum.
      [PJC]

WordNet (r) 3.0 (2006):

indumentum
    n 1: a covering of fine hairs (or sometimes scales) as on a leaf
         or insect [syn: indumentum, indument]