Source : Webster's Revised Unabridged Dictionary (1913)

Bracken \Brack"en\, n. [OE. braken, AS. bracce. See {2d Brake},
   n.]
   A brake or fern. --Sir W. Scott.

Source : WordNet®

bracken
     n 1: fern of southeastern Asia; not hardy in cold temperate
          regions [syn: {Pteridium esculentum}]
     2: large coarse fern often several feet high; essentially weed
        ferns; cosmopolitan [syn: {pasture brake}, {brake}, {Pteridium
        aquilinum}]