Teachers in a broad sense refer to those who impart knowledge and experience, while teachers in a narrow sense refer to those who have received special education and training and are engaged in education and teaching in education (schools).

Teachers are professionals who perform their education and teaching duties, and undertake the mission of teaching and educating people, cultivating social builders and improving the quality of the people. Broadly speaking, teachers and educators are the same language; Teachers in a narrow sense refer to full-time teachers in schools.

The concept of "teacher" is related to the development of education and teachers' profession. Clan leaders and elders with production and life experience of ancient primitive tribes consciously spread their production knowledge and life experience, especially customs and codes of conduct, to the younger generation for the survival and development of the tribe itself, so they became the earliest part-time teachers. After the school came into being, full-time teachers appeared.