vanguardyoudaoicibaDictYouDict
vanguard: [15] Vanguards have nothing to do with guarding vans. The word denotes etymologically an ‘advance guard’. It is short for the long defunct avantgard, which was borrowed from Old French avant-garde, a compound formed from avant ‘in front’ and garde ‘guard’. (Its modern French descendant was reborrowed into English as avant-garde [20].)
=> avant-garde, guard
avant-garde (n.)youdaoicibaDictYouDict
(also avant garde, avantgarde); French, literally "advance guard" (see avant + guard (n.)). Used in English 15c.-18c. in a literal, military sense; borrowed again 1910 as an artistic term for "pioneers or innovators of a particular period." Also used around the same time in communist and anarchist publications. As an adjective, by 1925.
The avant-garde générale, avant-garde stratégique, or avant-garde d'armée is a strong force (one, two, or three army corps) pushed out a day's march to the front, immediately behind the cavalry screen. Its mission is, vigorously to engage the enemy wherever he is found, and, by binding him, to ensure liberty of action in time and space for the main army. ["Sadowa," Gen. Henri Bonnal, transl. C.F. Atkinson, 1907]
point man (n.)youdaoicibaDictYouDict
"one who leads a military patrol in formation in a jungle, etc.," 1944, from point (n.) in military sense of "small leading party of an advance guard" (1580s) + man (n.).