看得見的圖
打光的東西是真的一張圖，配在文字旁邊。
picture in a book · noun · C1
A picture in a book, magazine, or similar piece of writing, especially one that helps you understand it.
插圖
核心畫面
One way to hold it: something put beside an idea to throw light on it so you can finally see it. A page of words stays flat until a picture — or a story — lands next to it and the meaning becomes visible.
把一樣東西擺到某個想法旁邊，替它打光，讓人終於「看見」它。文字寫在那裡是平的，直到旁邊出現一張圖、或一個故事，意思才…更多收起
把一樣東西擺到某個想法旁邊，替它打光，讓人終於「看見」它。文字寫在那裡是平的，直到旁邊出現一張圖、或一個故事，意思才突然立體起來。所以這個字底下同時裝著兩種東西——書頁上的那張圖，和用來讓道理現形的那個例子——它們其實是同一個動作：讓看不見的變成看得見的。From the word’s history
From Latin illustrare "to light up, make bright" (in- + lustrare "to make bright"), so an illustration is literally what lights something up.
來自拉丁文 illustrāre「照亮、使明亮」（in- 加上 lustrāre「使發光」）。所以 illustration 字面上就是「打光的那個東西」——不管打光的是一張圖還是一個例子，動作是同一個：讓原本模糊的東西亮起來、被看見。這條線索把插圖和例證這兩個看似無關的意思接回同一個畫面。
Wiktionary (illustration, illustrate) — from Latin illūstrātiō, from illūstrō "to light up, illuminate, make clear"
Two branches
讓道理現形的例子
打光的東西不是圖，是一件真實發生過的事——它替抽象的說法做了同樣的照明工作。
clear example · noun · C1
A story, event, or action that shows very clearly that something is true or that it is really there.
例證
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。
illustrationnoun/ˌɪləsˈtɹeɪ̯ʃən/
- 1
The act of illustrating; the act of making clear and distinct.
- 2
The state of being illustrated, or of being made clear and distinct.
- 3
Something which illustrates; a comparison or example intended to make clear or apprehensible, or to remove obscurity.
- England will regard it as a measure of justice for Frank Lampard's disallowed goal against Germany in Bloemfontein at the 2010 World Cup - but it was also an illustration of how they rode their luck for long periods in front of a predictably partisan home crowd.
- 4
A picture designed to decorate a publication, or elucidate a literary work.
- The illustration showing the water cycle made it much easier to understand for the children.
- The sleeve of the band's new CD includes illustrations from deceased former members.
- 5
A calculated prevision of insurance premiums and returns (life insurance).
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。