A tendril is a thin, curling part of a climbing plant that wraps around supports like fences, poles, or other plants to help the plant grow upward toward sunlight. Picture a pea plant or grapevine sending out delicate, spiraling stems that coil around whatever they touch, like tiny green springs reaching out and grabbing hold.

Tendrils work through a fascinating process: when they brush against something solid, one side grows faster than the other, causing the tendril to curl around the support. Watch a cucumber plant closely over several days, and you'll see its tendrils slowly wind around a garden stake, anchoring the plant so it can climb higher instead of sprawling across the ground.

The word can also describe anything that curls or spirals in a similar way. A tendril of hair might curl against someone's forehead, or tendrils of smoke might spiral upward from a campfire. Writers use this image when they want to suggest something delicate, reaching, and curling: “Tendrils of fog crept through the valley.”