Something avant-garde is new and unusual, and nothing is newer or more unusual than the first wave of a military battle. That's the logic that went into the formation of the phrase, anyway, because avant-garde literally means "advance guard"- something that is pushing the limit, just like the actual unit. Avant is a word meaning "in front" or "before" and, through Old French, it comes from the Latin word abante, with the same definition. This easily breaks into the prefix ab-, meaning "of", and the root ante, meaning "before". Garde, meanwhile, is the cognate and etymon of the English word guard, and it derives from the verb guarder, meaning "to protect". This in turn originated from the Frankish phrase wardon, "to protect", from Proto-Germanic wardana, "to guard", from PIE wer, "to cover". That's all, folks!
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd