- 1高畫質的、高解析度的（一般就說 HD）
Showing a picture with a lot of fine detail, so that the image looks sharp and clear instead of soft and blurry. It is used about televisions, screens, cameras, video, and pictures. 'Definition' here does not mean the meaning of a word — it is an older, technical use meaning how clearly the edges and small details of an image can be seen. Technically it means the screen or the video is made of a very large number of tiny dots, so the small things stay clear. Almost everyone it to HD, and in speech HD is far more common than the full words: 'Is it in HD?' It works as an adjective before a noun — a high-definition television, high-definition video — and you will also see it written as one word or as HD. Note that the word is a moving target: what counted as high-definition fifteen years ago is ordinary now, and shops have moved on to '4K' and 'Ultra HD' to mean the newest, sharpest kind. People also use it outside technology, about anything seen in painful detail: 'I saw every in high definition.'
「high-definition」形容畫面的細節很多、很細緻，看起來清楚銳利，不會軟軟糊糊。常用來形容電視、螢幕、相機、影片或圖片，例如 a high-definition television（高畫質電視）。口語上大家幾乎都說 HD，例如「Is it in HD?」。
這裡的 definition 指的是畫面清晰的程度，不是字的意思。這個詞的標準一直在變：十五年前算高畫質，現在可能已經很普通，所以店家改用 4K 或 Ultra HD 來指最新、最清楚的規格。它也可以開玩笑地用在科技以外，例如「I saw every wrinkle in high definition.」，意思是把皺紋看得一清二楚。
組成high (高的) + definition (清晰度). definition 來自 define「劃出界線」——把邊界劃得越清楚，畫面就越銳利，所以「清晰度」和「定義」其實是同一個字。
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：
- high definition
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。