- incident
- 1412, "something which occurs casually in connection with something else," from L. incidentem (nom. incidens), prp. of incidere "happen, befall," from in- "on" + -cidere, comb. form of cadere "to fall" (see case (1)). Sense of "an occurrence viewed as a separate circumstance" is from 1462. Meaning "event that might trigger a crisis or political unrest" first attested 1913. Incidental "casual, occasional" first recorded in Milton (1644). Conversational use of incidentally for "by the way" first attested 1925.