Think of your own footprints behind you. To backtrack is to put your feet back into them, one at a time, until you are standing where you were before. The point is not simply going back; it is going back by the same route you made yourself.
backtrack 可以想成「照著自己剛剛留下的腳印往回走」。重點不在「回去」這兩個字，而在「同一條路」：你來的時候怎麼走，回去就怎麼走，一步一步退回剛才那個位置。只要看得到這個畫面，其他用法都只是換一種「路」。
From the word’s history
The source gives it simply as back + track. Track is the line you have made by moving, and back is the direction of return — so the two parts already say the whole picture.
來源直接把它拆成 back 加 track。track 是走過留下的痕跡或路線，back 是往回的方向。兩個部分合起來，就已經把核心畫面講完了：沿著自己留下的那條線往回退。
Wiktionary (kaikki extract, source_ref kaikki:3f6f69a190036ae4:908826735:17696)
登入就可以看每一支怎麼連回核心畫面。