The Collaborative International Dictionary of English v.0.48:

Liniment \Lin"i*ment\ (l[i^]n"[i^]*ment), n. [L. linimentum, fr.
   linire, linere, to besmear, anoint : cf. F. liniment. Cf.
   Letter, Lime a viscous substance.]
   A liquid or semiliquid preparation of a consistence thinner
   than an ointment, applied to the skin by friction, esp. one
   used as a sedative or a stimulant.
   [1913 Webster]

WordNet (r) 3.0 (2006):

liniment
    n 1: a medicinal liquid that is rubbed into the skin to relieve
         muscular stiffness and pain [syn: liniment,
         embrocation]