The Collaborative International Dictionary of English v.0.48:

Trichome \Trich"ome\, n. [See Trichomatose.] (Bot.)
   A hair on the surface of leaf or stem, or any modification of
   a hair, as a minute scale, or star, or gland. The sporangia
   of ferns are believed to be of the nature of trichomes. --
   Tri*chom"a*tous, a.
   [1913 Webster]