Bracket

Round brackets ( )

are used to enclose a list of numbers to be pre- or post-multiplied or to enclose the arguments of a function; they also occur in expressions.

Square brackets [ ]

are used to enclose a list of option settings or to enclose the suffix list of a pointer; also, when preceded by $, they enclose lists of unit names or numbers for a qualified identifier.

Curly brackets { }

are each synonymous with the corresponding square bracket.