boot camp

Short definition from Wiktionary

Noun

1. 1
   Initial, basic indoctrination, physical fitness training and basic instruction in service-related subjects for new recruits in the armed forces (army, Air Force, navy and Marine Corps).
2. 2
   A short, intensive, quasi-military program generally aimed at young offenders as an alternative to a jail term.
3. 3
   Any short, often intensive course of training.