1475, "to keep up, maintain," from M.Fr. entretenir, from O.Fr. entretenir "hold together, support," from entre- "among" (from L. inter) + tenir "to hold" (from L. tenere; see tenet). Sense of "have a guest" is 1490; that of "amuse" is 1626. Entertainer "public performer" is from c.1535.
