NBC is one of the main American television companies. The letters stand for National Broadcasting Company. For a long time it was one of the three big US networks that families watched at home, together with ABC and CBS. You still see the name on news, talk shows, and big nights. Write it in capital letters; it is a name, not a normal word. Though actually, the same three letters can mean something else in a science or army class (a warning about dangerous materials). If you are reading about TV, films, or US news, NBC is the television company.