Falx

noun

1. A sickle-shaped anatomical structure.
2. A metal implement, of a form suitable for a pruning-hook, sometimes found among ancient remains.
3. In anatomy, something which is falcate or falciform; specifically, a fold of the dura mater separating parts of the brain. See falx cerebri and falx cerebelli, below.
4. In herpetology, one of the poison-fangs of a serpent: so called from its shape: generally used in the plural.
5. In entomology, one of the jointed appendages under the front of a spider's cephalothorax, used to seize and kill its prey.