- 1約、大約（寫在年份前面的書面縮寫）
In writing, especially about history, ca. is a short way of writing the Latin word circa, which means "about" or "around" when you talk about a date. You put it before a year when nobody is sure of the exact year: ca. 1800 means "sometime around 1800". You will see it on museum labels, in books, and on timelines. It is a writing habit, not a speaking one — people do not usually say "ca" out loud; they say "about" or "around". Though actually, some writers use c. with only one letter, and it means the same thing. The little dot is part of the abbreviation, like other short forms in careful writing.
ca. 是拉丁文 circa 的縮寫，意思是大約或左右，寫在年份前面，表示確切年代不確定。像「ca. 1800」就是大約 1800 年前後，你會在博物館標示牌、書籍和年表上看到它。
它是書寫用的縮寫，說話時一般不會唸 ca，而是說 about 或 around。有些作者會只用一個字母 c.，意思完全一樣。寫的時候，後面的點是縮寫的一部分。
組成Short written form of Latin circa, "around / about".
同家族的字
- circathe full Latin word that ca. shortens
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。
這個拼法也被記錄為下列字的變化形：
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。