The Collaborative International Dictionary of English v.0.48:

harakiri \ha"ra*ki`ri\, hara-kiri
\ha"ra-ki`ri\(h[add]"r[add]*k[=e]`r[i^]), n. [Jap., stomach
   cutting.]
   A ritual form of suicide, by slashing the abdomen, formerly
   practiced in Japan, and commanded by the government in the
   cases of disgraced officials; disembowelment; -- also
   written, but incorrectly, hari-kari. --W. E. Griffis.
   [1913 Webster]

WordNet (r) 3.0 (2006):

harakiri
    n 1: ritual suicide by self-disembowelment on a sword; practiced
         by samurai in the traditional Japanese society [syn:
         harakiri, hara-kiri, harikari, seppuku]