A Master of Science is a postgraduate academic

Postgraduate education

Postgraduate education involves learning and studying for degrees or other qualifications for which a first or Bachelor's degree generally is required, and is normally considered to be part of higher education...

 master's degree

Master's degree

A master's is an academic degree granted to individuals who have undergone study demonstrating a mastery or high-order overview of a specific field of study or area of professional practice...

 awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.
In Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

 and Uruguay

Uruguay

Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...

, the Master of Science or Magister is a postgraduate degree of two to four years of duration. The admission to a Master program (Castilian: Maestría; Portuguese: Mestrado) in an Brazilian, Argentine or Uruguayan University requires the full completion of an undergraduate degree, as well Licentiate

Licentiate

Licentiate is the title of a person who holds an academic degree called a licence. The term may derive from the Latin licentia docendi, meaning permission to teach. The term may also derive from the Latin licentia ad practicandum, which signified someone who held a certificate of competence to...

's degree as Professorate degree of four to five years long from any recognized university.