• 卒業そつぎょう — graduation
• 新卒しんそつ — new graduate
• 兵卒へいそつ — foot soldier
• 卒倒そっとう — fainting; collapse

卒 originally depicted ceremonial attire and order, pointing to completion. The meaning broadened to include “soldier,” and by extension “to finish” a stage such as schooling or service.