貼在牆側面的那層材料
這一支把「旁邊」讀成房子的側面：一片片長板疊在外牆上，替牆擋雨擋太陽。
noun · B2
Long narrow boards or strips of wood, metal, or plastic that are fixed side by side over the outside walls of a house to cover and protect them.
外牆板
核心畫面
Something that belongs at the side rather than in the middle: not the wall itself but the layer laid over its side, not the main line but the short track laid alongside it.
siding 可以想成「在旁邊的那個」。不是牆本身，是釘在牆側面的那層板；不是主線，是鋪在主線旁邊的那段軌。兩個意思…更多收起
siding 可以想成「在旁邊的那個」。不是牆本身，是釘在牆側面的那層板；不是主線，是鋪在主線旁邊的那段軌。兩個意思都從 side 長出來，重點都不在主體，而在貼著主體、幫主體擋一下或空出來的那一層、那一條。From the word’s history
Both senses are side plus -ing, but Wiktionary files them as two separate formations: one -ing meaning material or collection, the other forming a noun from side.
兩個意思都是 side 加 -ing，但 Wiktionary 把它們分成兩條不同的造字路線：一條的 -ing 是「一批材料」（像 roofing、flooring），另一條的 -ing 是單純把 side 變成名詞。所以它們同根，但不是一個從另一個變出來的。
Wiktionary entries for siding, etymology 1 (source_ref kaikki:3f6f69a190036ae4:1262224427, side + -ing 'material, collection') and etymology 3 (source_ref kaikki:3f6f69a190036ae4:1262231663, side + -ing 'derivative noun').
Two branches
鋪在主線旁邊的那段軌
同樣是「旁邊」，只是這次旁邊的對象不是牆，而是主線鐵軌。
noun · C1
A short piece of railway track joined to the main track at one end or both, used for keeping trains out of the way, for loading them, or for letting another train pass.
側線
原始詞典資料3 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
sidingnoun詞源 1/ˈsaɪdɪŋ/
- 1
A building material which covers and protects the sides of a house or other building.
- Ugh. If there's one thing I can't stand it's cheesy vinyl siding.
sidingnoun詞源 3/ˈsaɪdɪŋ/
- 1
rail-transportrailwaystransportA second, relatively short length of track just to the side of a railroad track, joined to the main track by switches at one or both ends, used either for loading or unloading freight, storing trains or other rail vehicles; or to allow two trains on a same track to meet (opposite directions) or pass (same direction) (the latter sense is probably an American definition).
- They slept where they could, sometimes in an empty truck on a siding near the station, sometimes in a cart behind a warehouse; [...]
- Laid out over six square kilometres, Sellafield is like a small town, with nearly a thousand buildings, its own roads and even a rail siding – all owned by the government, and requiring security clearance to visit.
這個拼法也被記錄為下列字的變化形：
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。