cactus: [17] Cactus comes via Latin from Greek káktos, which was the name of the cardoon, a plant of the thistle family with edible leafstalks. Cactus originally had that meaning in English too, and it was not until the 18th century that the Swedish botanist Linnaeus applied the term to a family of similarly prickly plants.
c. 1600, from Latin cactus "cardoon," from Greek kaktos, name of a type of prickly plant of Sicily (the Spanish artichoke), perhaps of pre-Hellenic origin. Modern meaning is 18c., because Linnaeus gave the name to a group of plants he thought were related to this but are not.
