Board Thread:False Info and Speculative Discussion/@comment-26835511-20150729230437/@comment-4091815-20150730185721

Prep means "college preparatory"

As for lower grades, it varies by school district in the US.

Some areas have "Junior High" which covers grades 7-9.

Some have "Middle School" which covers grades 6-8.

The traditional "Elementary School" model has grades 1-3 and 4-6.