Русско-англо-русский юридический словарь

Repeating A Year (also known as ​“grade retention”, ​“non-promotion”, or ​“failing a grade”) describes the process by which pupils who do not reach a given standard of learning at the end of a year are required to join a class of younger students the following academic year. (EEF)

Grade retention or grade repetition is the process of a student repeating a grade after failing the previous year. (Wikipedia)