The Tooth FamilyRadical 牙
A whole life in one set of teeth
ShuowenShuowen: “Tooth (牙), the back teeth (mǔ-chǐ). Drawn as upper and lower interlocking.”
牙 and 齿 were kept apart by the ancients: front teeth are 齿, back teeth are 牙 — the oracle form of 牙 shows upper and lower molars locking. The tooth radical is small, but dense with stories: 穿 is “a tooth at work in a hole” (to bore through); 雅 was originally the crow (borrowed for “elegant”, hence 雅言, the standard tongue); 讶 is the sound of meeting something unexpected. And 龄 takes the tooth radical — age was once recorded on the teeth: read the mouth, and you know the years.
The Root Character · Reading “牙” in Three Layers
See the form
Upper and lower teeth interlocking — 牙 is the grinding molar.
Read the logic
牙 and 齿 divided the work: 齿 names the front teeth in general, 牙 the chewing molars — “clench the teeth and grind (咬牙切齿)”: front and back working at once.
Grasp the wisdom
牙牙学语 — a person’s first words are spoken by a mouth whose teeth have only just come in. Teeth record age (齿龄), and growth too.
The Making of a Glyph
- Oracle boneUpper and lower molars interlocked.
- BronzeThe locking teeth full and sharp.
- Small sealCurves entangled, teeth grinding.
- Clerical & regularFour strokes fix the form: 牙.
Glyphs are schematic reconstructions, not rubbings.
The Chain of Teeth
One set of teeth is a well-drilled crew: the cutters, the tearers, the grinders, and the last to arrive — each with its own name.
By function — each with its postMilk teeth — a person’s first set, twenty in all.
The 牙 of 牙牙学语 is this set: only when they come in does the talking start.
Character Assembly · Two Parts Become One
When two parts walk toward each other, a new character is born. Watch how they meet.
穿 chuān
FormA tooth (牙) at work in a cave (穴).
LogicTo bore through with teeth is 穿 — to pierce, to thread.
Wisdom穿针, 穿凿, 看穿 — “piercing” began with teeth biting through: getting through anything takes that steady bite.
雅 yǎ
FormThe tooth (牙) beside a bird (隹) — originally the crow!
Logic雅 was the original character for 鸦, the crow; later borrowed to mean “correct” — hence 雅言, the standard speech.
WisdomA crow lent its character to “elegance” — 优雅, 典雅, 风雅: the finest word has the plainest origin.
讶 yà
FormWords (讠) beside a tooth (牙) as sound.
LogicTo meet and cry out is 讶 — the sound of surprise at first sight.
Wisdom惊讶 — 讶 is the gasp at the unexpected: the sound arrives before the thought, teeth before words.
呀 yā
FormThe mouth (口) beside a tooth (牙) as sound.
LogicThe sound of a mouth opening — both an exclamation and an onomatopoeia.
Wisdom呀 is the tooth’s registered sound: a door opens — “ya!”; a person stumbles — “ya!” — the shortest human cry of surprise.
Branches of the Family
Hover (or tap) a character to see what it means.
Kin of the 齿
齿 and 牙 divided the work — 齿 characters live round the mouth and the years.
- 齿
- 龋
- 龄
- 啮
- 龂
- 龃
- 龉
- 龁
The Tooth Clan
The tooth radical is small, but every member has a story.
- 穿
- 雅
- 讶
- 迓
- 伢
- 蚜
- 呀
- 芽
「A ready tongue and sharp teeth are no match for dealing in good faith.」
—— Proverb
「A tooth for a tooth, an eye for an eye.」
—— Code of Hammurabi