signyoudaoicibaDictYouDict[sign 词源字典]
sign: [13] Sign comes via Old French signe from Latin signum ‘mark’. It already had the meaning ‘mark denoting something’ in Latin, and it was in this sense that it entered English, gradually ousting the native word token. The verb sign goes back ultimately to the Latin derivative signāre ‘mark’. English acquired it in the 14th century, and first used it for ‘write one’s name’ in the 15th century.

Other related forms in English include assign [14], consign [15], design, ensign [14], insignia [17], resign [14] (in which the prefix re- has the force of ‘un-’), seal ‘wax impression, fastening’, signal, signatory [17], signature [16], signet [14], significant [16], and signify [13].

The ultimate source of Latin signum is uncertain. It was once assumed to go back to the Indo-European base *sek- ‘cut’ (source of English saw, section, etc), as if it denoted etymologically a ‘cut mark’, but now Indo-European *seq- ‘point out’, hence ‘say, tell’ (source of English say) is viewed as a more likely ancestor.
=> assign, consign, design, ensign, insignia, resign, seal, signal, signature, significant[sign etymology, sign origin, 英语词源]
sign (n.)youdaoicibaDictYouDict
early 13c., "gesture or motion of the hand," especially one meant to communicate something, from Old French signe "sign, mark," from Latin signum "identifying mark, token, indication, symbol; proof; military standard, ensign; a signal, an omen; sign in the heavens, constellation," according to Watkins, literally "standard that one follows," from PIE *sekw-no-, from root *sekw- (1) "to follow" (see sequel).

Ousted native token. Meaning "a mark or device having some special importance" is recorded from late 13c.; that of "a miracle" is from c. 1300. Zodiacal sense in English is from mid-14c. Sense of "characteristic device attached to the front of an inn, shop, etc., to distinguish it from others" is first recorded mid-15c. Meaning "token or signal of some condition" (late 13c.) is behind sign of the times (1520s). In some uses, the word probably is a shortening of ensign. Sign language is recorded from 1847; earlier hand-language (1670s).
sign (v.)youdaoicibaDictYouDict
c. 1300, "to make the sign of the cross," from Old French signier "to make a sign (to someone); to mark," from Latin signare "to set a mark upon, mark out, designate; mark with a stamp; distinguish, adorn;" figuratively "to point out, signify, indicate," from signum (see sign (n.)). Sense of "to mark, stamp" is attested from mid-14c.; that of "to affix one's name" is from late 15c. Meaning "to communicate by hand signs" is recorded from 1700. Related: Signed; signing.