STEM is consist of 4 majors:

• Science
• Technology
• Engineering
• Mathematics

Science -  is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.

Technology - is the collection of techniques, skills, methods and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques, processes, etc. or it can be embedded in machines, computers, devices and factories, which can be operated by individuals without detailed knowledge of the workings of such things.

Engineering - is the collection of techniques, skills, methods and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques, processes, etc. or it can be embedded in machines, computers, devices and factories, which can be operated by individuals without detailed knowledge of the workings of such things.

Mathematics -  is the study of topics such as quantity (numbers),structure, space, and change. There is a range of views among mathematicians and philosophers as to the exact scope and definition of mathematics.

Science, Technology, Engineering and Mathematics (STEM, previously SMET) is an acronym that refers to the academic disciplines of science, technology, engineering and mathematics. The term is typically used when addressing education policy and curriculum choices in schools to improve competitiveness in science and technology development. It has implications for workforce development, national security concerns and immigration policy.

The acronym arose in common use shortly after an interagency meeting on science education held at the US National Science Foundation chaired by the then NSF director Rita Colwell. A director from the Office of Science division of Workforce Development for Teachers and Scientists, Peter Faletra, suggested the change from the older acronym METS to STEM. Colwell, expressing some dislike for the older acronym, responded by suggesting NSF to institute the change. One of the first NSF projects to use the acronym was STEMTEC, the Science, Technology, Engineering and Math Teacher Education Collaborative at the University of Massachusetts Amherst, which was funded in 1997.