Thorns are sharp, pointed structures that grow on a variety of plants, including roses, blackberries, and cacti. Synonyms for "thorn" include "prickle," which refers to a sharp point or spine; "thistle," which is a prickly plant with purple flowers; "spine," which is a pointed projection on a plant's stem or branch; and "barb," which is a sharp projection that can hook onto clothing or flesh. Other words that may be used in place of "thorn" include "splinter," "spicule," and "stinger." Whether you're talking about a rose bush, a cactus, or a bramble patch, these synonyms can help you describe the sharp and prickly nature of thorns.