TPACK stands for Technological Pedagogical Content Knowledge. It is a theory that was developed by Punya Mishra and Matthew J. Koehler of Michigan State University in 2006 to explain the set of knowledge that teachers need to teach their students a subject, teach effectively, and use technology.
Furthermore, it is a framework that helps to understand and describe the kinds of knowledge needed by a teacher for effective pedagogical practice in a technology-enhanced learning environment.