Wiktionary
cram school
n. A specialised school that trains students to meet particular goals, most commonly to pass the entrance examinations of high schools or universities.
Wikipedia
Cram school
Cram schools or as a whole, crammers, are specialized schools that train their students to meet particular goals, most commonly to pass the entrance examinations of high schools or universities. The English name is derived from the slang term " cramming", meaning to study hard or to study a large amount of material in a short period of time.
Usage examples of "cram school".
In the end he was accepted by Costello's Academy, a cram school that operated out of a dilapidated Victorian mansion on the other side of Rondebosch common, and was not particular about its admissions.