noun, noun which may take the genitive case particle 'no'
residential; training-camp-style; boarding
Describes an event, course, or program where participants stay together at a facility, often for intensive training or study. Commonly used as a modifier with の.
This seminar will be held in a residential training-camp style.
I participated in a boarding-style training session.
合宿 refers to the training camp or lodging together itself, while 合宿形式 describes the style or format of an event as being like a training camp.
Compound of 合宿 (がっしゅく, 'lodging together, training camp') and 形式 (けいしき, 'form, style').