ambushyoudaoicibaDictYouDict[ambush 词源字典]
ambush: [14] Originally, ambush meant literally ‘put in a bush’ – or more precisely ‘hide in a wood, from where one can make a surprise attack’. The hypothetical Vulgar Latin verb *imboscāre was formed from the prefix in- and the noun *boscus ‘bush, thicket’ (a word of Germanic origin, related to English bush). In Old French this became embuschier, and when English acquired it its prefix gradually became transformed into am-.

In the 16th century, various related forms were borrowed into English – Spanish produced ambuscado, Italian was responsible for imboscata, and French embuscade was anglicized was ambuscade – but none now survives other than as an archaism.

=> bush[ambush etymology, ambush origin, 英语词源]
ambush (v.)youdaoicibaDictYouDict
c. 1300, from Old French embuscher (13c., Modern French embûcher) "to lay an ambush," from en- "in" + busch "wood," apparently from Frankish *busk "bush, woods" (see bush (n.)). Related: Ambushed; ambushing.
ambush (n.)youdaoicibaDictYouDict
late 15c., embushe, from the English verb or from Middle French embusche, from Old French embuscher (see ambush (v.)). Earlier was ambushment (late 14c.). Figurative use by 1590s.