refresher course

noun

noun

A short course of additional training or updating knowledge of one's profession.

Another example of the quality of staff is the percentage of passes achieved by firemen after a refresher course of one week on driving steam locomotives—until recently a necessary qualification for a diesel driver, even within a fully dieselised scheme.1962 October, M. J. Wilson, “Three years of dieselisation at Devons Road depot”, in Modern Railways, page 264:

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.