We don't have synonyms for prep schools yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are prep school, pre school and preschools.
(n) :
(US) A private or public school intended to prepare its students to gain admission into prestigious universities.
(n) :
(British) A private primary school which prepares its pupils for the common entrance examination most commonly at the age of thirteen, and subsequent entry into public school.
(n) :
(US) A private or public school intended to prepare its students to gain admission into prestigious universities.
(n) :
(British) A private primary school which prepares its pupils for the common entrance examination most commonly at the age of thirteen, and subsequent entry into public school.