The Collaborative International Dictionary of English v.0.48:

Hypochondrium \Hy`po*chon"dri*um\, n.; pl. L. Hypochondria, E.
   Hypochondriums. [L., fr. Gr. ?, from ? under the cartilage
   of the breastbone; ? under + ? cartilage.] (Anat.)
   Either of the hypochondriac regions.
   [1913 Webster]