Lantern wheel, also known as a crown wheel or a contrate wheel, is a type of gear commonly used in automobiles and other machinery. Synonyms for this term include spur gear, bevel gear, and straight-cut gear. Spur gear is a type of lantern wheel with straight teeth that are mounted parallel to the gear axis while bevel gear is a lantern wheel with angled teeth that mount perpendicularly to the gear axis. Straight-cut gear is another term for spur gear and refers to its straight teeth. While each term may have slight variations in design and usage, they are all used to refer to the same type of gear - the lantern wheel.