The Collaborative International Dictionary of English v.0.48:

Decant \De*cant"\, v. t. [imp. & p. p. Decanted; p. pr. & vb.
   n. Decanting.] [F. d['e]canter (cf. It. decantare), prop.,
   to pour off from the edge of a vessel; pref. d['e]- (L. de) +
   OF. cant (It. canto) edge, border, end. See Cant an edge.]
   To pour off gently, as liquor, so as not to disturb the
   sediment; or to pour from one vessel into another; as, to
   decant wine.
   [1913 Webster]