As part of education in the United States, the definition of secondary education varies among school districts but generally comprises grade 7 (age 12--13), grade 8 (age 13--14), and grade 9 (age 14--15) through grade 12 (age 17--18); grade 5 (age 10--11) and grade 6 (age 11--12) are also sometimes included. Grades 9 through 12 is the most common grade structure for high school.

Is it true that is secondary education and high school the same?
no