- 1藉此、從而、因而（強調「靠這個動作」才造成結果）
"Thereby" means "and by doing that" — it links an action to the result that the action itself produces. Its favourite shape is "thereby + -ing": "The company moved production to Vietnam, thereby cutting its costs by half." That means: the moving is what cut the costs. It is not just "and then"; it says the first thing was the METHOD of the second. Compare "so" or "therefore", which only say one thing followed from another. It is formal and written — reports, essays, legal writing, news analysis. In speech people say "and that way", "and so", or just start a new sentence: "...and that cut costs by half." There is also one famous fixed phrase you will meet in stories and articles: "thereby hangs a tale", which means "there is an interesting story behind that" — it comes from Shakespeare and is used with a smile, not literally.
From the word’s history
From Middle English therby, from Old English ðǣrbig; equivalent to there + by.
源自古英文 ðǣrbig，就是 there 加 by。
組成there + by. Again "there" means "that" — so literally "by that", i.e. by that means, by doing that.
原始詞典資料1 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，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。
therebyadv/ðɛɹˈbaɪ/
- 1
formalBy it; by that; by that means, or as a consequence of that.
- I enrolled in Old English classes and thereby learned much about Germanic languages.
- Thirdly, Whereas the Maintenance of an hundred thouſand Children, from two Years old, and upwards, cannot be computed at leſs than Ten Shillings a piece per Annum, the Nation's ſtock will be thereby encreaſed fifty thouſand pounds per Annum, beſides the profit of a new Diſh, introduced to the Tables of all Gentlemen of Fortune in the Kingdom, who have any refinement in Taſte, and the Money will circulate among our ſelves, the Goods being entirely of our own Growth and Manufacture.
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。