Английский Этимологический словарь - close (adj.)

- c.1380, "strictly confined," also "secret," from O.Fr. clos "confined," from L. clausus, pp. of claudere "stop up, fasten, shut," sense shifting to "near" (1488) by way of "closing the gap between two things." Close call is 1881; close shave is 1834; close quarters is 1753, originally nautical.