1. (Science: zoology) The tusk of an animal, by which the prey is seized and held or torn; a long pointed tooth; especially, one of the usually erectile, venomous teeth of serpents. Also, one of the falcers of a spider. Since i am a dog, beware my fangs. (Shak)
6. The valve of a pump box. A bend or loop of a rope. In a fang, fast entangled. To lose the fang, said of a pump when the water has gone out; hence: to fang a pump, to supply it with the water necessary to make it operate.