XML is a way of writing information in a plain text file so that both a computer and a person can see what each piece of the information IS, not just what it says. You wrap each piece in a tag: <price>250</price> says "this 250 is a price". Tags can sit inside other tags, so a whole thing with parts — a book with a title, an author, a year — keeps its shape. That shape is the point.

XML is a way of writing information in a plain text fileXML 是一種把資訊寫成純文字檔的方法, so that both a computer and a person can see what each piece of the information IS讓電腦和人都能看出每一段資訊「是什麼」, not just what it says而不只是它寫了什麼內容。You wrap each piece in a tag你把每一段資訊包在一個標籤裡: <price>250</price> says "this 250 is a price"<price>250</price> 就是在說「這個 250 是一個價格」。Tags can sit inside other tags標籤可以放在標籤裡面, so a whole thing with parts所以一個有很多部分組成的整體 — a book with a title, an author, a year像一本書有書名、作者、年份 — keeps its shape能保持住它的結構。That shape is the point這個結構就是重點。

Because the labels travel with the data, one program can send a file to a completely different program, on a different computer, written by different people, and the second one can still find the price, because it just looks for the price tag. Before this, programs each had their own private file format and could not read each other's.

Because the labels travel with the data因為標籤是跟著資料一起走的, one program can send a file to a completely different program一個程式可以把檔案送給完全不同的另一個程式, on a different computer, written by different people在不同的電腦上、由不同的人寫的, and the second one can still find the price第二個程式還是找得到那個價格, because it just looks for the price tag因為它只要找 price 這個標籤就好。Before this在這之前, programs each had their own private file format每個程式都有自己私有的檔案格式 and could not read each other's彼此讀不懂對方的檔案。

The letters stand for Extensible Markup Language. "Markup" means the tags added around the text; "extensible" means you invent your own tag names — XML does not come with a list of tags, it only tells you the rules for writing them. That is the difference from HTML, which has a fixed set of tags (p, div, a) for one job, showing pages in a browser.

The letters stand for Extensible Markup Language這幾個字母代表 Extensible Markup Language（可延伸標記語言）。"Markup" means the tags added around the text"Markup" 是指加在文字周圍的標籤; "extensible" means you invent your own tag names"extensible" 是指你可以自己發明標籤名稱 — XML does not come with a list of tagsXML 本身沒有附帶一份標籤清單, it only tells you the rules for writing them它只告訴你寫標籤的規則。That is the difference from HTML這就是它跟 HTML 不同的地方, which has a fixed set of tags (p, div, a) for one jobHTML 有一組固定的標籤（p、div、a），只做一件事, showing pages in a browser就是在瀏覽器裡顯示網頁。

It is a countable-ish technical noun, mostly used without an article: "the settings are in XML", "we export XML", "an XML file", "XML format". You will meet it in app settings files, in older company systems, in ebooks (EPUB), in office documents (.docx is XML inside a zip), and in RSS feeds. In new work people often choose JSON instead, which is shorter and easier to read, so XML now feels a bit old-fashioned — but it is everywhere in systems that already exist, and it is not going away.

It is a countable-ish technical noun它算是一個介於可數不可數之間的技術名詞, mostly used without an article大多不加冠詞使用: "the settings are in XML", "we export XML", "an XML file", "XML format"像 "the settings are in XML"、"we export XML"、"an XML file"、"XML format"。You will meet it in app settings files, in older company systems你會在應用程式設定檔、比較舊的公司系統裡碰到它, in ebooks (EPUB)在電子書格式（EPUB）裡, in office documents (.docx is XML inside a zip)在辦公室文件裡（.docx 其實就是壓縮檔裡包著 XML）, and in RSS feeds還有 RSS 訂閱源裡。In new work people often choose JSON instead新的專案裡大家常常改用 JSON, which is shorter and easier to read因為它比較短、比較好讀, so XML now feels a bit old-fashioned所以 XML 現在感覺有點過時 — but it is everywhere in systems that already exist但它在既有的系統裡到處都是, and it is not going away而且不會消失。