Canteen means: A small cafeteria or snack bar, especially one in a military establishment, school, or place of work.. It is military jargon and mostly appears in service contexts, war fiction, or among veterans and their families. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. As a place or proper-name reference it is purely descriptive. It is an education-system term, so usage is institutional and routine.