英语词源字典 - 在线词源网站

secure (adj.)[secure 词源字典]: 1530s, "without care, dreading no evil," from Latin securus, of persons, "free from care, quiet, easy," also in a bad sense, "careless, reckless;" of things, "tranquil; free from danger, safe," from *se cura, from se "free from" (see secret (n.1)) + cura "care" (see cure (n.)).

In English, of places, "free from danger, unexposed," from 1580s. Meaning "firmly fixed" (of material things) is from 1841, on notion of "affording grounds for confidence." Of telephones, "not wiretapped," from 1961. Replaced Middle English siker, from Old English sicor, from the Latin word. Related: Securely.[secure etymology, secure origin, 英语词源]
wire-tapping (n.): also wiretapping, "surreptitiously obtaining information by connecting wires to telegraph (later telephone) lines and establishing an intermediate station between two legitimate ones," 1878, from wire (n.) + agent noun from tap (v.2). Earliest references often are to activity during the American Civil War, but the phrase does not seem to have been used at that time. Related: Wire-tap; wire-tapper.