Noun
a spring in the shape of a coil
Source: WordNetIn 1912, Harley-Davidson introduced their patented "Ful-Floteing Seat", which was suspended by a coil spring inside the seat tube. citation The spring tension could be adjusted to suit the rider's weight. Source: Internet
In the process, Hooke demonstrated a pocket-watch of his own devising, fitted with a coil spring attached to the arbour of the balance. Source: Internet
In these clutches, a coil spring is wrapped around the driven shaft and held in an expanded configuration by the trip lever. Source: Internet