In English usage, should one use high-school, high school, or highschool? (Assume American English; I understand that the Brits call it secondary school.) High-school, with the hyphen, is correct when the term is used as an adjective, e.g., I lost my high-school diploma. Saludos.

Understanding the Context

If you think there's such a thing as "High School English" (as opposed to simply saying She teaches English at high school) then you should probably capitalize it to reflect that. But personally, I think only non-native speakers would think like that. When I say 'She teaches high school English', do I use H and S as ... I would have answered that the terms "Primary School" and "Grade School" both refer to elementary, middle, and high school collectively.

Key Insights

According to Wikipedia, the government considers "elementary school" to cover anything up to grade 8, whereas in my experience it's only considered to extend to grade 5. In BrE you only graduate from university (or other tertiary institution); in AmE you also graduate from high school (secondary school). A person who graduates (or who has graduated) is a graduate. The verb is pronounced with a full final vowel ['grædʒueɪt], the noun with a weak vowel ['grædʒuət]. It is normally a simple active verb: he graduated in 1978.

Final Thoughts

It is unusual, and I think quite ... 1 Published instances of phrases of the type "X High School varsity football team" in Google Books search results show considerable variation in initial capitalization. The vast majority capitalize "X High School" (presumably because the authors recognize that they are dealing with a proper name). (At my high school the graduating class simply voted for its valedictorian, making it essentially a popularity contest.) Furthermore, while valedictorians are common at U.S. high schools and colleges, I don't recall having ever heard of one at the elementary school level, which is what you say you're focusing on. 1 A professor is one who teaches in a university or college whereas a teacher is the one who teaches in high schools and comprehensive schools.

It is normally only used for a college or university, not for a high school; the last would sound a bit silly and pretentious. However, silly and pretentious can be humorous, so talking about your primary school as your alma mater can be appropriate if you are being ironic. What do you call a student who has completed year 12/senior year of high school and are about to begin 1st year/freshman year of uni/college but have not started yet? Happy for both US and UK versions.