The Collaborative International Dictionary of English v.0.48:

Bast \Bast\, n. [AS. b[ae]st; akin to Icel., Sw., Dan., D., & G.
   bast, of unknown origin. Cf. Bass the tree.]
   1. The inner fibrous bark of various plants; esp. of the lime
      tree; hence, matting, cordage, etc., made therefrom.
      [1913 Webster]

   2. A thick mat or hassock. See 2d Bass, 2.
      [1913 Webster]

WordNet (r) 3.0 (2006):

bast
    n 1: strong woody fibers obtained especially from the phloem of
         from various plants [syn: bast, bast fiber]
    2: (botany) tissue that conducts synthesized food substances
       (e.g., from leaves) to parts where needed; consists primarily
       of sieve tubes [syn: phloem, bast]
    3: cat- or lion-headed Egyptian goddess; represents life-giving
       power of the sun