Mercury \m(e)-rcu-ry, mer-cury\ as a boy's name is of Latin origin, and the meaning of Mercury is "commerce". In modern usage, the name is sometimes a nickname for fleet-footed runners. Mythology: the messenger of the Gods who corresponds to the Greek Hermes. Its ancient root also evolved into terms such as "merchant", "market", and "mercenary", showing the influence of the wing-footed Roman god of science and commerce, and the bustle of commercial life. A sixth-century priest named Mercury changed his name to John after he was elected to the papacy, since he felt it was inappropriate for a pope to have the name of a pagan god. Football player Mercury Morris.