The Collaborative International Dictionary of English v.0.48:

Lanolin \Lan"o*lin\ (l[a^]n"[-o]*l[i^]n), n. [L. lana wool +
   oleum oil.] (Physiol. Chem.)
   A peculiar fatlike body, made up of cholesterin and certain
   fatty acids, found in feathers, hair, wool, and keratin
   tissues generally.
   [1913 Webster]

   Note: Under the same name, it is prepared from wool for
         commercial purposes, and forms an admirable basis for
         ointments, being readily absorbed by the skin.
         [1913 Webster] lansa

WordNet (r) 3.0 (2006):

lanolin
    n 1: a yellow viscous animal oil extracted from wool; a mixture
         of fatty acids and esters; used in some ointments and
         cosmetics [syn: lanolin, wool fat, wool grease]
    2: an emollient containing wool fat (a fatty substance obtained
       from the wool of sheep)