You can think of echelon as one rung of a ladder. Set several things out so that each one stands a step above, behind or to the side of the last, and you get a slanting, line — planes in the sky, rows of numbers on a page, or people in an organization. Whatever the material, the picture is the same: not one flat row, but a staircase, where every position sits at a different step.
echelon 可以想成梯子上的一階。把東西一個一個錯開擺，每一個都比前一個高一階、或退一階，整排就成了一道斜斜的階梯。飛過天空的飛機是這樣，紙上整理好的矩陣是這樣，公司裡一層一層的職位也是這樣。共同的畫面不是一條平平的直線，而是一道樓梯：每個位置都站在不同的那一階上。
From the word’s history
Borrowed from French échelon, a rung of a ladder, a diminutive of échelle (ladder), which goes back to Latin scāla. The ladder is still visible in every modern use.
借自法文 échelon，意思是梯子的一橫、一階；它是 échelle（梯子）的小稱形，再往前是拉丁文 scāla。今天每一個用法裡，那把梯子都還在。
Wiktionary, "echelon"
登入就可以看每一支怎麼連回核心畫面。