The Collaborative International Dictionary of English v.0.48:

Flagellation \Flag`el*la"tion\, n. [L. flagellatio: cf. F.
   flagellation.]
   A beating or flogging; a whipping; a scourging. --Garth.
   [1913 Webster]

WordNet (r) 3.0 (2006):

flagellation
    n 1: beating as a source of erotic or religious stimulation
    2: beating with a whip or strap or rope as a form of punishment
       [syn: whipping, tanning, flogging, lashing,
       flagellation]