The Collaborative International Dictionary of English v.0.48:

Friday \Fri"day\, n. [AS. friged[ae]g, fr. Frigu, the gooddes of
   marriage; friqu love + d[ae]g day; cf. Icel. Frigg name of a
   goddess, the wife of Odin or Wodan, OHG. Fr[imac]atag, Icel.
   Frj[=a]dagr. AS. frigu is prob. from the root of E. friend,
   free. See Free, and Day.]
   The sixth day of the week, following Thursday and preceding
   Saturday.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Friday
    n 1: the sixth day of the week; the fifth working day [syn:
         Friday, Fri]