regulation that is enacted by a school and whose students must obey; school regulation

the way in which something is tightly packed or close together without gaps

(rare, archaic) wondrous, miraculous, splendid, sublime / (rare, archaic) dignified, solemn, stern, noble, refined / (rare, archaic) beautiful, pretty

stern, grave, forbidding; dignified, stately / strict, unforgiving / tight, close, without gaps / harsh, tough, extreme, severe, hard to withstand (said of natural phenomena)

school (institution dedicated to teaching and learning)

ridiculous (oppressive, etc.) school regulation

(historical) elementary school, national elementary school

school supported by a pro-North Korean organization

school supported by a pro-South Korean organization

school grammar / (specifically) Japanese school grammar, based on Shinkichi Hashimoto's work and now universally employed in Japanese schools and dictionaries.