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A backslash is the mark \ — a thin line that leans back, the other way from the usual slash /. In ordinary English you almost never need it. Writers use the forward slash in dates, fractions, and “and/or.” The backslash belongs to computers: Windows file paths often use it to separate folder names, and some kinds of code use it as a special signal (for example, to say “the next mark is special”). People mix the two marks constantly, and keyboards do not help — they sit near each other. The name is a small picture: think of a standing bar |. If it topples “back” against the way we write (left to right), you get \; if it topples forward, you get /. (If you write the marks by hand from the top down, the hand actually moves the other way — which is why the names feel slightly upside-down once you think about it.) Unicode’s official name for \ is “reverse ,” but nobody in class needs that; “backslash” is the word they will hear.
反斜線（對岸較常說「反斜杠」）
組成From back + slash: it is a slash “leaning back” against the direction of writing (left to right), in contrast to the common forward slash /. The name treats a standing bar | as a person who topples backwards (\) or forwards (/).
同家族的字
- slashthe mark / that leans the other way; a backslash is that mark leaning back
原始詞典資料3 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。
backslashnoun/ˈbækˌslæʃ/
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The punctuation mark \ (a left-leaning diagonal line). (Common uses include (1) use as a delimiter in filepaths and (2) use as an escape character to mark literals.)
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rarecomputingengineeringmathematicsThe punctuation mark /; a slash, forward slash.
- […] I was trying to find a web-site for which I had been given the following address: http://www.isop.ucla.edu/pacrim/pubs/korjournal.htm. […] I began to work backwards, removing first the last part of the address following the last backslash (/korjournal.htm).
- “So, do what I tell you. Open a browser window and type this in the menu^([sic]) bar: F-T-P colon backslash backslash euronews dot net backslash...” I pecked carefully at the keyboard as he dictated a URL that was about fifty characters long, […]
backslashverb/ˈbækˌslæʃ/
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computingengineeringmathematicsTo escape (a metacharacter) by prepending a backslash that serves as an escape character, thereby forming an escape sequence.
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。