In many universities in the US, students choose a primary specialty to study (called their "major") and optionally a secondary emphasis (called a "minor"). How would these terms be expressed in Spanish when referring to a US education? And do universities in Spanish-speaking countries have the same major/minor structure?
I asked this same question of my Spanish teacher who spent significant amounts of time in Spain (was married to a Spaniard and spent summers there.) His suggestion was to refer to the major as "especialización" and minor as "subespecialización". These are the best descriptions I've heard for describing the US system of study in Spanish terms.
In Colombia (and in most Latin American counties) there is no such structures in undergraduate education. Therefore, "major" and "minor" words are used only to speak about US educational system.
Instead, in most latin american countries we have a system that differentiates between "professional" and "technician" education (educacón profesional y educación técnica o tecnológica). A professional degree is better that a technician degree. The former is taught at Universities and have a duration of 4 to 5 years. The later is taught at "Institutos Técnicos" and usually have a duration of 2 to 3 years.
There is some similarities between major and professional degrees, and between minor and technician degrees, but our education systems are different from yours in many details.
If you are talking about education you must be careful to refer to a specific country (for example: Perú, Mexico or Brasil), and make a research about the specific names that are used there to refer to their specific structures in education. A Wikipedia search is often enough.