One of the two canonical (i.e. standard or normal) forms of a Boolean function, useful in comparing and simplifying functions. This form contains one standard sum term, or maxterm, for each ‘zero’ (false) entry in the truth table for the expression. This form can be represented as the AND (product) of a group of ORs (the sum terms) of Boolean variables, uncomplemented or complemented. It can also be shown to be the NOR of a group of NORs of the identical variables. Compare standard sum of products.