lowest common denominator

Universal Words noun 1 (mathematics) (abbreviation LCD) the smallest number that the bottom numbers of a group of FRACTIONS can be divided into exactly 2 (disapproving) something that is simple enough to seem interesting to, or to be understood by, the highest number of people in a particular group; the sort of people who are least intelligent or accept sth that is of low quality: The school syllabus seems aimed at the lowest common denominator.