potionem (nominative: potio), meaning "a drinking" or "a drink", and more specifically "a poisonous drink", as seen in the writings of Cicero. The Latin root comes from the verb potare, meaning "to drink".

The use of "poison" as an adjective in the form "poisonous" dates back to the 1520s. The practice of using "poison" in combination with plant names began in the 18th century. For example, the term poison oak was first recorded in 1743, and poison ivy