1. According to a regular pattern; natural (it is normal to be nervous in court). • The term describes not just forces that are constantly and habitually operating but also forces that operate periodically or with some degree of frequency. In this sense, its common antonyms are unusual and extraordinary.
2. According to an established rule or norm (it is not normal to deface statues).
3. Setting a standard or norm (a normal curriculum was established in the schools).