late 14c., meloun, "herbaceous, succulent trailing annual plant," or its sweet, edible fruit, from Old French melon (13c.) and directly from Medieval Latin melonem (nominative melo), from Latin melopeponem, a kind of pumpkin, from Greek mēlopepon "gourd-apple" (name for several kinds of gourds bearing sweet fruit), from mēlon "apple" (see malic) + pepon, a kind of gourd, which is probably a noun use of pepon "ripe" (see pumpkin).
Among the earliest plants to be domesticated. In Greek, melon was used in a generic way for all foreign fruits (compare similar use of apple). The Greek plural of "melon" was used from ancient times for "a girl's breasts."