"Cactus" is an ancient Greek term for a spiny plant. When first used it referred to cardoon, the artichoke. Wild artichokes have stout spines on the edible bracts. Cultivated artichoke varieties have lost those spines. The word was adopted to refer to what we now know as cacti when the first plants were brought back to Europe by the early explorers. Now it "only" refers to the members of the cactus family (Cactaceae).