What is broadly elliptical. Oval chuck (Mech.), a lathe chuck so constructed that work attached to it, and cut by the turning tool in the usual manner, becomes of an oval form called?

oval — (Bot.) Broadly elliptical. Oval chuck (Mech.), a lathe chuck so constructed that work attached to it, and cut by the turning tool in the usual manner, becomes of an oval form. (Webster's 1913.)

Sources