徹 — penetrate, clear, pierce, strike home, sit up (all night)

Readings

On'yomi

テツ

Example words

• 徹底てっていthoroughness; completeness; consistency
• 徹夜てつやall night; all-night vigil; sleepless night
• 徹するてっするto sink in; to penetrate; to devote oneself; to believe in; to go through; to do intently and exclusively