The Free On-line Dictionary of Computing (30 December 2018):

sum of products

   1.  Any mathematical expression in which
   an addition operator is applied to two or more subexpressions
   each of which is an application of a multiplication operator.
   The most common case would be scalar addition and
   multiplication, e.g.

   	ab + cd

   but the term is used for other kinds of operators with similar
   properties, such as AND and OR in Boolean algebra, e.g.

   	(a AND b) OR (c AND d)

   2.  algebraic data type.

   (2008-02-04)