APA Dictionary of Psychology

a type of two-way table used to display and analyze data for two dichotomous variables. For example, suppose a survey of a group of 100 participants reported information on two variables: (a) year in college(freshman or sophomore) and (b) major in college (social sciences or humanities). The results could be shown in a two-by-two table. Also called fourfold table; two-by-two contingency table.