sign of aggregation
noun Mathematics.
any of the signs used to indicate grouping in an algebraic expression: vinculum, bar, or raised horizontal line, 
; a pair of parentheses, (a + b); a pair of brackets, [a + b]; or a pair of braces, {a + b}.
; a pair of parentheses, (a + b); a pair of brackets, [a + b]; or a pair of braces, {a + b}.Origin of sign of aggregation
First recorded in 1940–45
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Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019