The Collaborative International Dictionary of English v.0.48:

Satyr \Sa"tyr\ (?; 277), n. [L. satyrus, Gr. ?: cf. F. satyre.]
   1. (Class. Myth.) A sylvan deity or demigod, represented as
      part man and part goat, and characterized by riotous
      merriment and lasciviousness.
      [1913 Webster]

            Rough Satyrs danced; and Fauns, with cloven heel,
            From the glad sound would not be absent long.
                                                  --Milton.
      [1913 Webster]

   2. (Zool.) Any one of many species of butterflies belonging
      to the family Nymphalidae. Their colors are commonly
      brown and gray, often with ocelli on the wings. Called
      also meadow browns.
      [1913 Webster]

   3. (Zool.) The orang-outang.
      [1913 Webster]

WordNet (r) 3.0 (2006):

satyr
    n 1: man with strong sexual desires [syn: satyr, lecher,
         lech, letch]
    2: one of a class of woodland deities; attendant on Bacchus;
       identified with Roman fauns [syn: satyr, forest god]

The Devil's Dictionary (1881-1906):

SATYR, n.  One of the few characters of the Grecian mythology accorded
recognition in the Hebrew.  (Leviticus, xvii, 7.)  The satyr was at
first a member of the dissolute community acknowledging a loose
allegiance with Dionysius, but underwent many transformations and
improvements.  Not infrequently he is confounded with the faun, a
later and decenter creation of the Romans, who was less like a man and
more like a goat.