The Collaborative International Dictionary of English v.0.48:

Boneset \Bone"set`\ (-s[e^]t`), n. (Bot.)
   A medicinal plant, the thoroughwort (Eupatorium
   perfoliatum). Its properties are diaphoretic and tonic.
   [1913 Webster]

WordNet (r) 3.0 (2006):

boneset
    n 1: European herb having small white, pink or purple flowers;
         naturalized as a weed in North America [syn: common
         comfrey, boneset, Symphytum officinale]
    2: perennial herb of southeastern United States having white-
       rayed flower heads; formerly used as in folk medicine [syn:
       boneset, agueweed, thoroughwort, Eupatorium
       perfoliatum]