Source : Webster's Revised Unabridged Dictionary (1913)

Flannel \Flan"nel\ (fl[a^]n"n[e^]l), n. [F. flanelle, cf. OF.
   flaine a pillowcase, a mattress (?); fr. W. gwlanen flannel,
   fr. gwlan wool; prob. akin to E. wool. Cf. {Wool}.]
   A soft, nappy, woolen cloth, of loose texture. --Shak.

   {Adam's flannel}. (Bot.) See under {Adam}.

   {Canton flannel}, {Cotton flannel}. See {Cotton flannel},
      under {Cotton}.

Source : WordNet®

flannel
     n 1: a soft light woolen fabric; used for clothing
     2: bath linen consisting of a piece of cloth used to wash the
        face and body [syn: {washcloth}, {washrag}, {face cloth}]
     3: (usually in the plural) trousers [syn: {gabardine}, {tweed},
         {white}]
     [also: {flannelling}, {flannelled}]