A serpent is a snake, especially a large or dangerous one. The word sounds more dramatic and mysterious than “snake,” which is why you'll often find it in myths, legends, and old stories. The serpent in the Garden of Eden tempted Eve to eat the forbidden fruit. Ancient Greeks told of enormous serpents guarding treasures. In many cultures, serpents symbolize both danger and wisdom because of their silent, watchful nature and deadly venom.

The word can also describe someone who acts like a snake: sneaky, untrustworthy, or secretly harmful. If a character in a novel is called serpentine, they might be smooth-talking on the surface but plotting something devious underneath. A serpent's movement, winding and curving, gives us the word serpentine to describe anything that twists and turns like a snake, such as a serpentine mountain road that winds back and forth up a steep slope.

While “snake” is the everyday word, “serpent” adds a sense of danger, ancient power, or mythical quality. You'd call the garter snake in your backyard a snake, but you'd call the great, dragon-like creature in a fantasy story a serpent.