The Collaborative International Dictionary of English v.0.48:

Parnassian \Par*nas"sian\, a. [L. Parnassius.]
   Of or pertaining to Parnassus.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Parnassian \Par*nas"sian\, n. [See Parnassus.] (Zool.)
   Any one of numerous species of butterflies belonging to the
   genus Parnassius. They inhabit the mountains, both in the
   Old World and in America.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Parnassian \Par*nas"sian\, n. [F. parnassien.]
   One of a school of French poets of the Second Empire
   (1852-70) who emphasized metrical form and made little use of
   emotion as poetic material; -- so called from the name
   (Parnasse contemporain) of the volume in which their first
   poems were collected in 1866.
   [Webster 1913 Suppl.]