蓋在上面的那一層
這一組都在講「那一層東西」，差別只在它是自然落下的，還是特地做來鋪上去的。
noun · B1
A layer of something lying over a surface, so that the surface is protected or hidden — snow on a field, dust on a shelf, or a cloth over a chair.
覆蓋物
核心畫面
Picture one thing lying on top of another. The thing underneath is still there — you simply cannot see it or reach it any more. That top layer is what the word points at, whether it is snow on a field, paper on a wall, or a sheet over a chair.
可以想成一層東西平平地躺在另一樣東西上面。下面那樣東西沒有消失，只是被遮住、被保護起來了。雪蓋住草地、灰積在架子上、…更多收起
可以想成一層東西平平地躺在另一樣東西上面。下面那樣東西沒有消失，只是被遮住、被保護起來了。雪蓋住草地、灰積在架子上、布罩著椅子，畫面都是同一個：上面多了一層。這個字大部分的用法，都在講那一層；少數時候，它講的是「把那一層放上去」這個動作。From the word’s history
The noun comes from Middle English coverynge, the verbal noun of coveren 'to cover' — or, read another way, cover plus -ing. Either route gives the same picture: the -ing form names what the covering does and what it leaves behind.
根據資料來源，這個名詞來自中古英文 coverynge，是動詞 coveren（蓋）的動名詞；也可以看成 cover 加上 -ing。兩種說法指向同一件事：-ing 一邊指「蓋」這個動作，一邊指這個動作留下來的那一層，所以這個字才會同時有這兩種用法。
Wiktionary (kaikki extract), source_ref kaikki:3f6f69a190036ae4:816191639:12818 — "From Middle English coverynge, -inge, keverynge, -inge [verbal noun of coveren, keveren (to cover)]; or, verbal noun from cover (verb) + -ing."
Two branches
蓋上去這個動作
-ing 名詞常常一邊指動作、一邊指結果，這一支走的是動作那一邊。
noun · B2
The act of putting something over a thing. Used as an uncountable noun, usually as 'the covering of' plus what is being covered.
覆蓋（這個動作）
原始詞典資料5 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。
coveringnoun詞源 2/ˈkʌvəɹɪŋ/
- 1
That which covers or conceals; a cover; something spread or laid over or wrapped about another.
- Face covering is also mentioned: "There are some circumstances when wearing a face covering may be marginally beneficial as a precautionary measure. The evidence suggests that wearing a face covering does not protect you, but it may protect others if you are infected but have not yet developed symptoms. [...] If you can, wear a face covering if you need to use public transport."
- 2
Action of the verb to cover.
- 3
mathematicssciencestopologyA collection of sets U_i such that their union contains U; such a collection with the additional property that every U_i is open; such a collection with the additional property that every U_i is contained in U.
- 4
mathematicssciencestopologyA special kind of map that establishes a relationship between two topological spaces in the sense that, under the action of the map, the one looks locally like several copies of the second: Formally, a continuous map π:E→X between topological spaces such that there exists, for every point x in X, a discrete space D_x and an open neighborhood U of x such that π⁻¹(U)= displaystyle ⨆_(d∈D_x)V_d and π|_(V_d):V_d→U is a homeomorphism for every d∈D_x. See Covering space on Wikipedia.Wikipedia
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。