在英语中，「brackets」和「parentheses」指的都是括号，因此容易混淆。一般来说，parentheses 指的是圆括号 ( )，而 brackets 指的是方括号 [ ]。然而，现在的人已经倾向直接称圆括号为「round brackets」，而方括号则称为「square brackets」。
方括号的用途并不如圆括号那麽广泛，技术手册会较常出现。而圆括号的用法跟逗号相似，用来补充与句中重点相关的资讯丶事后个人的想法或做评论，但这两者仍有区别。许多文法学者都认为，几乎所有情况下都可用逗号来取代圆括号。
举例
- The government's education report (April 2005) shows that the level of literacy is rising in nearly all areas.
- I visited Kathmandu (which was full of tourists) on my way to the Himalayas for a trekking expedition.
- You can eat almost anything while travelling in Asia if you are careful to observe simple rules (avoiding unboiled or unbottled water is one of the main rules to be aware of.)