\lbrack \rbrackSquare brackets are used as delimiters in mathematical expressions to group terms or denote intervals. They are often used to clarify the order of operations or to specify the domain of a function.
Closed interval from a to b
[a, b]Function notation using square brackets
f[x] = x^2 + 2x + 1Grouping terms to clarify order of operations
[x + y] * z