ancientyoudaoicibaDictYouDict[ancient 词源字典]
ancient: [14] Like antique, ancient was originally, in Latin, an adjectivized version of the adverb and preposition ‘before’: to ante ‘before’ was added the adjective suffix -ānus, to produce the adjective *anteānus ‘going before’. In Old French this became ancien, and it passed into English via Anglo-Norman auncien. The final -t began to appear in the 15th century, by the same phonetic process as produced it in pageant and tyrant. The now archaic use of ancient as ‘standard, flag’ and as ‘standard-bearer’ (as most famously in Shakespeare’s ‘ancient Pistol’) arose from an alteration of ensign.
=> antique[ancient etymology, ancient origin, 英语词源]
ancient (adj.)youdaoicibaDictYouDict
mid-14c., auncyen, from Old French ancien "old, long-standing, ancient," from Vulgar Latin *anteanus, literally "from before," adjectivization of Latin ante "before, in front of, against" (from PIE *anti "against," locative singular of *ant- "front, forehead;" see ante). The parasitic -t dates from 15c. by influence of words in -ent.

Specifically, in history, "belonging to the period before the fall of the Western Roman Empire" (and contrasted with medieval and modern). In English law, "from before the Norman Conquest." Ancient of Days is from Dan. vii:9. Related: Anciently.
ancient (n.)youdaoicibaDictYouDict
"standard-bearer," 1550s, a corruption of ensign. Archaic, but preserved in Shakespeare's character Aunchient Pistoll in "Henry V."