表面的光，以及移到抽象事物上的光
這一支就是核心畫面本身，以及它往抽象方向再走一步的結果。
noun · C1
The soft, attractive shine on the surface of something such as hair, pearls, silk, metal or polished wood, seen when light falls on it and comes back.
光澤
核心畫面
One way to hold this word: a surface that gives light back. Light falls on hair, on a pearl, on polished wood, and the surface answers with a soft, even shine of its own. Nothing is burning and nothing is flashing. The thing simply looks alive under the light, and that look is what lustre names.
可以想成一個「會把光回敬給你」的表面。光照到頭髮、珍珠、木頭、金屬上，表面就柔柔地亮起來。它自己不發光，也不刺眼，只…更多收起
可以想成一個「會把光回敬給你」的表面。光照到頭髮、珍珠、木頭、金屬上，表面就柔柔地亮起來。它自己不發光，也不刺眼，只是把光穩穩地送回你眼睛裡。lustre 講的就是那個「亮起來的樣子」。因為要有這層光，東西通常得乾淨、完好、保養得好——所以這個字順便帶著「狀態不錯」的感覺。From the word’s history
The shine word came into English from Middle French lustre.
「光澤」這一支是從中古法文 lustre 借進英文的；同一個字的美式拼法是 luster。
Wiktionary etymology for lustre (etymology 1), supplied in evidence packet (kaikki:3f6f69a190036ae4:961484793)
Two branches
五年為一段的時間（另一條來源）
這一支跟「光」沒有關係，不要硬接回核心畫面；它只是碰巧拼法相同。
noun · C2
A period of five years, used mainly in writing about ancient Rome.
五年（一段時期）
原始詞典資料4 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。
lustrenoun詞源 1/ˈlʌstə/
- 1
UK standard spelling of luster (shine, etc.).
- Various kinds of minerals differ in their lustre; iron pyrites are described as having a metallic lustre, glassy materials a vitreous lustre; others, such as opal, look resinous, and the lustres of yet others are described as being either pearly, or silky, or dull, like earth.
- In the centre is painted an eagle, from whose beak an elegant glass lustre chandelier is suspended. There are also ten smaller chandeliers in different parts of the room.
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。