[ 'trəʊkɔɪd ]
■ adjective
1》 Anatomy denoting a joint in which one element rotates on its own axis (e.g. the atlas vertebra).
2》 Geometry denoting a curve traced by a point on a radius of a circle rotating along a straight line or another circle.
3》 Zoology (of a mollusc shell) conical with a flat base.
■ noun
1》 a ~ curve.
2》 a ~ joint.
Derivatives
~al adjective
Origin
C18: from Gk trokhoeidēs 'wheel-like', from trokhos 'wheel'.