Chainwheels

Part of speech: noun

Definitions

1. Toothed gears attached to the pedals and rear hub that carry the drive chain of a bicycle
2. The sprocket wheels around which a bicycle chain runs to transfer pedaling power to the back wheel
3. Notched discs on a bike's crank and cassette that engage the links of the chain to move the cycle forward

Etymology: Chainwheels are a plural form, so the substance lies in its parts: "chain" and "wheel," each with a long lineage of its own. "Chain" traces back through Old French "chaeine" to Latin "catēna," meaning a fetter or link, and the Latin word probably goes back to an Italic root. "Wheel" descends from Old English "hwēol," a Germanic word whose ancestors reach back to a very old Indo-European root meaning to turn or revolve. A chainwheel is simply a wheel that carries or engages a chain, most familiarly the toothed sprocket on a bicycle or motorcycle that drives the chain around. The compound is transparent: a chain and a wheel joined together, with no special history attached to the joining itself.