For our purposes, hemp is the plant called cannabis sativa. There are other plants that are called hemp, but cannabis hemp is the most useful of these plants. In fact, cannabis sativa means "useful (sativa) hemp (cannabis)". "Hemp" is any durable plant that has been used since pre-history for many purposes. Fiber is the most well known product, and the word "hemp" can mean the rope or twine which is made from the hemp plant, as well as just the stalk of the plant which produced it. Cannabis is also the most durable of the hemp plants, and it produces the toughest cloth, called "canvass". Canvass was widely used as sails in the early shipping industry, as it was the only cl