牙yá

Modern simplified form (簡體). 牙 (yá, "tooth") is a pictograph of a molar, its jagged outline capturing the shape of a tooth with remarkable clarity. As a radical, 牙 appears in characters such as 穿 (to pierce), 邪 (evil), and 鸦 (crow), lending its meaning of "tooth" or "bite" to many words. The character has remained unchanged from ancient oracle bone script to the modern simplified form, showing the enduring power of its visual metaphor.