academy (specialized school), vocational school

private school (US), public school (UK)

military academy, (especially) the Imperial Japanese Naval Academy

driving school

(education) high school, senior high school

(idiomatic) to have grown tense (of a situation); to have become critical (and to be on the verge of a major upheaval)

school for special needs

six-year secondary school (type of school introduced in the 1998 revision of the Japanese School Education Law)

(computer science) steepest descent method