falx

(historical) A short Dacian sword resembling a sickle.

(anatomy) A curved fold or process of the dura mater or the peritoneum, especially one of the partition-like folds of the dura mater which extend into the great fissures of the brain.

(anatomy, dated) A chelicera.

(anatomy) A snake's poison fang.

(anatomy) A rotula of a sea urchin.