Twine is a strong thread, light string or cord composed of two or more thinner strands twisted, and then twisted together (plied). The strands are plied in the opposite direction to that of their twist, which adds torsional strength to the cord and keeps it from unravelling. This process is sometimes called reverse wrap. The same technique used for making twine is also used to make thread, which is thinner, yarn, and rope, which is stronger and thicker, generally with three or more strands.
Natural fibres used for making twine include wool, cotton, sisal, jute, hemp, henequen, paper, and coir. A variety of synthetic fibres are also used. Twine is a popular substance used in modern-day crafting.
The invention of twine is at least as important as the development of stone tools for early humans. Indeed, Elizabeth Wayland Barber has called the development of twine, which can be made far stronger and longer than its component fibers, "the string revolution." Twine could be used to fasten points and blades to arrows, spears, harpoons and other tools and to make snares, bags, baby slings, fishing and hunting nets and marine tackle, not to mention to secure firewood, haul goods and anchor tents and shelters. Twine is the foundation to both textile and rope making. Twine has been made of animal hair, including human, sinews and plant material, often from the vascular tissue of a plant (known as bast), but also bark and even seed down, e.g. milkweed. However, unlike stone or metal tools, most twine is missing from the archaeological record because it is made of perishable materials that rarely survive over time. In fact, the discovery of ancient beads and the dating of sea travel to at least 60,000 years ago suggests that the "string revolution" might have occurred much earlier than the Upper Paleolithic. Plant twine was used for hafting stone tips by about 58 000 years ago in southern Africa.
Paleolithic cord remnants have been discovered in a few places: Georgia's Dzudzuana Cave (30,000 years old), Israel's Ohalo II site (19,000 years old), and France's Lascaux Cave (17,000 years old).