Difference between "senior high school" and "high school"?

There is no senior high, its just 12th grade.

Senior High School and High School are the same thing. I'm not sure why some say Senior High School and a high school senior does mean you're in 12th grade.

Back in 1968, when I was in the 7th grade, in Junior High School. My school district built a second high school. They decided to move the 9th grade into the high schools. The junior high became a middle school and they moved some of the 6th graders into the middle school. In the 7th grade, Junior High, each class could have any student in the school taking or retaking each individual class you were taking. When I was in the 8th grade, Middle School now, half the day we were in classes with the same students of the same grade. Math, English and Social Studies were the classes, I think? These three classes were like Elementary School, the other half of the day was like Junior High School was before. I was told back then that a Senior High School does not have the 9th grade in it, and a High School does have the 9th grade.

severe church: a superb style of formality; Catholics, Episcopalians, Lutherans, some Methodists Low church: no longer very a lot ritual; Presbyterians, Nazarenes, "non-denominational Christian" In between: Baptists, some Methodists, LDS

The word Senoir in front.