denoting a joint in which one element rotates on its own axis (e.g. the atlas vertebra)

denoting a curve traced by a point on a radius of a circle rotating along a straight line or another circle (a cycloid, epicycloid, or hypocycloid)

having or denoting a form of mollusc shell which is conical with a flat base, like a top shell

a trochoid curve

a trochoid joint