One way to hold this word: a thing standing in the middle of the floor with nothing behind it and nothing under it. Take away the wall, the bracket, the frame — it is still upright. Because nothing is holding it, you could also carry it somewhere else and it would be just as complete there. Every use of freestanding is that same check: is anything holding this up, or does it stand by itself?
From the word’s history
The source gives the word as free + standing. Free here is the sense of not being tied to anything, and standing is being upright, so the compound is literally standing without being tied to something else.
字源資料直接寫 freestanding 是 free 加 standing。free 在這裡不是「免費」，而是「沒有被綁住」；standing 是「站著的狀態」。合起來字面就是「沒被綁住地站著」。這個字面意思幾乎就是它今天的全部用法，只是「被綁住」的對象從牆變成了制度、論點或作業系統。
Wiktionary (kaikki extract, source_ref kaikki:3f6f69a190036ae4:688745994:14980): "From free + standing"
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