Anything that's coiled is arranged in a tight circle of rings. If you can stomach it, picture a coiled snake and you'll get the idea.
New sailors have to watch out for swinging sails overhead and coiled rope underfoot. Your pet snakes might sleep in a coiled heap, and your little sister's fancy hairdo may consist of many coiled sections of hair pinned to her scalp. The adjective coiled describes something that takes the shape of a coil, a circle, ring, or spiral. The Latin root is colligere, "to gather together."