- complex
- c.1652, "composed of parts," from Fr. complexe, from L. complexus "surrounding, encompassing," pp. of complecti "to encircle, embrace," from com- "with" + plectere "to weave, braid, twine." The adj. meaning "not easily analyzed" is first recorded 1715. Psychological sense of "connected group of repressed ideas" was established by C.G. Jung, 1907. Complex sentence is attested from 1881.