There is no difference between both the terms. High School is the correct word whereas highschool is not right word.
The difference is easy to understand.
- High school is correct.
- Highschool is incorrect.
Here’s how high school is used in the English language:
High school, in the United States and Canada, is the education students receive from approximately 13 to 18 years old. Most comparable to secondary schools, high schools generally deliver phase three of the ISCED model of education. High schools have subject-based classes. The name high school is applied in other countries, but no universal generalization can be made as to the age range, financial status, or ability level of the pupils accepted. In North America, most high schools include grades nine through twelve and students attend them following junior high school (middle school).