括弧 (kuò hú) is a noun meaning 'bracket'—specifically the curved symbols used in writing and mathematics, such as parentheses ( ), square brackets [ ], or curly braces { }. Though less common than 括号 (kuò hào), 括弧 emphasizes the 'curved' shape of these symbols (弧 means 'arc' or 'curve'), making it especially appropriate when discussing typographic form or handwriting. It’s often used in educational, technical, or publishing contexts where precise terminology matters.

The character 括 means 'to enclose' or 'to include', while 弧 refers to a curved line—so together, 括弧 literally suggests 'an enclosing curve'. While both 括弧 and 括号 refer to brackets, 括弧 carries a slightly more formal or descriptive nuance and appears more frequently in textbooks, style guides, or discussions about punctuation design rather than casual speech.