The terms "college" and "university" are often used interchangeably. A university is usually comprised of multiple degree-conferring colleges. The University of Wyoming is comprised of six colleges with a set number of degree options and academic departments.
Undergraduate programs follow high school and lead to an associate's (two-year) degree or a bachelor's (four-year) degree. The University of Wyoming does not offer associate degrees, but many community colleges offer them. Graduate programs follow a bachelor’s degree and lead to a master’s or doctoral degree (PhD).
Essentially there is no difference.
An undergraduate major is the study of a body of knowledge in a subject area of interest. Most undergraduate majors at the University of Wyoming result in either a Bachelor of Science degree or a Bachelor of Arts degree.
A concentration (also called option or program area) is a collection of courses within a major that focuses on a particular subject area. Not all majors require the selection of a concentration. International Studies and Family and Consumer Sciences are just two examples of UW majors that do require this.