Lee Shulman clearly identified six things that makes teaching a profession. The first of the six is Service. Teaching is a profession because it is a service, and the teachers are more knowledgeable about the information that they teach compared to most other people. Teaching has its own calling and ethics, which is one reason teaching is a profession. Another reason teaching is a profession, is because of Theory.
Theory relates to having the knowledge base and the skills to teach others.
This is a standard that is accepted by the public, which classifies teaching as a profession. Practice is the third thing that identifies teaching as a profession. Where the teaching takes place. One of the things to consider with Practice is whether or not the place where teachers do their work is actually working. The students need to be able to receive the material in a good environment.