1510s, "serving as an organ or instrument," from Latin organicus, from Greek organikos "of or pertaining to an organ, serving as instruments or engines," from organon "instrument" (see organ). Sense of "from organized living beings" is first recorded 1778 (earlier this sense was in organical, mid-15c.). Meaning "free from pesticides and fertilizers" first attested 1942. Organic chemistry is attested from 1831.