Here is a comprehensive summary of the Wikipedia article on brackets:

Brackets are paired punctuation marks used to isolate text or data, and they come in four main shapes: round ( ), square [ ], curly { }, and angle ⟨ ⟩—with terminology varying between British and American English (e.g., "round brackets" vs. "parentheses"). Historically, angle brackets were the earliest form in English, while Erasmus coined the term lunula for round brackets, and modern standardization arrived with the ASCII character set in 1961, which included parentheses, square, and curly brackets. The most common type, parentheses (round brackets), are used to add supplementary information, clarifications, or asides—such as "Senator John McCain (R – Arizona)"—and also serve practical shorthand like indicating singular/plural ("claim(s)") or gender-neutral forms ("(s)he"). These marks have been famously employed in stream-of-consciousness literature by authors like William Faulkner and poet E. E. Cummings. In typography, English convention generally avoids italicizing brackets even when they enclose italic text, unlike German practice. Additionally, brackets can be nested, and in mathematics they carry specific meanings for denoting functions and subformulas.