the word adultery originates not from “adult”, as is commonly thought in english-speaking countries, but from the late latin word for “to alter, corrupt”: “adulterare”. “adulterare” in turn is formed by the combination of “ad” (towards), and “alter” (other), together with the infinitive form “are” (making it a verb). thus the meaning is literally “to make other”. in contrast, the word “adult” (meaning a person of mature years) comes from another latin root, “adolescere”, meaning to grow up or mature: a combination of “ad” (towards), “alere” (to nourish, to grow), and the inchoative infix “sc”(meaning to enter into a state of).