Origin

This character combines the disease or illness radical on the left (the roof-like shape that classifies medical conditions) with a component on the right that sounds like "tou" — the sound hint that guides pronunciation. The left side signals we're talking about a sickness, while the right side tells you roughly how to say the word. Together they create a character specifically for pox and smallpox, one of the most feared diseases in East Asia. The character's structure follows a common Japanese pattern of stacking a meaning indicator with a sound clue to build new medical and technical terms.