The acronym STEM stands for Science, Technology, Engineering and Math. However, in the classroom STEM means much more than the bare addition of those four subjects.
STEM means the integration of those subjects and also implies a certain way to work with them. In fact, most teachers associate it with collaborative work, with active learning and with project/problem-based learning.
The stem4math model summarizes what STEM is and how it should be approached in the classroom.