典礼 (diǎn lǐ) is a formal, grand ceremony held for important occasions (graduation, opening, national day). Compared to 仪式 (yí shì), which is a broader term for any ceremony or ritual, 典礼 implies greater formality and scale. It also differs from 庆典 (qìng diǎn), which focuses on celebration and festivity, while 典礼 emphasizes solemnity and procedural order.