A double major is a student who completes two sets of degree requirements. Double majors or dual majors consist of two majors attached to a single degree, as opposed to two separate degrees each with its own field of study. In some schools, students will earn a double major when the two majors lead to the same degree name, and they will earn a double degree when the two majors lead to differently-named degrees.
Double Major means you get a single degree from one university, but with an objective in two related subject areas. Typically this means you satisfy the core requirements of both programs, possibly using the electives of one to fill in the core of the other.