The Collaborative International Dictionary of English v.0.48:

Tinto \Tin"to\, n. [Pg., tinged, fr. L. tinctus, p. p. of
   tingere to tinge. See Tint, n.]
   A red Madeira wine, wanting the high aroma of the white
   sorts, and, when old, resembling tawny port.
   [1913 Webster]