Key Facts
- Hangul: 이; Revised Romanization: i
- Part of speech: noun
- Origin: native
- Register: Neutral everyday word; 치아 is the formal/medical term.
Tooth in Korean: How Do You Pronounce 이?
One syllable: i. Because it is so short, 이 is almost always heard together with a particle or a verb, as in 이가 or 이를. Those endings are what tell you the tooth is meant.
Example Sentences with 이
이가 아파요.
Iga apayo
My tooth hurts.
A complaint at the dentist: 이가 pairs the tooth with the subject particle, and 아파요 says it hurts.
매일 이를 닦아요.
Maeil ireul dakkayo
I brush my teeth every day.
A habit. 매일 is every day, and 이를 닦아요 uses the verb 닦다, to wipe or brush.
이가 빠졌어요.
Iga ppajyeosseoyo
A tooth fell out.
A child or accident sentence. 빠졌어요 is the past of 빠지다, to fall out.
Common Phrases and Collocations
| Korean | Meaning |
|---|---|
| 이를 닦다 | to brush one's teeth |
| 이가 빠지다 | for a tooth to fall out |
| 이가 아프다 | to have a toothache |
이를 닦다, 이가 빠지다 and 이가 아프다 are three verbs for three situations: care, loss and pain.
The Mistake to Avoid
Mistake: reading every 이 as the same word. 이 can be the tooth, the Sino-Korean number two, "this", or the subject particle.
Correction: look at its partners. A particle after it (이가, 이를) plus a verb such as 아파요 or 닦아요 means the tooth; 이 directly before a noun means "this".
이 Compared with Similar Words
치아 is the formal or medical word, suited to a clinic form. 이빨 is casual and mostly for animals, and for people it can sound rude.
| Word | Meaning | How to tell them apart |
|---|---|---|
| 이 | tooth | This page's word |
| 치아 | teeth (formal) | 치아 is the formal/medical term for teeth. |
| 이빨 | teeth (casual/animal) | 이빨 is casual and mostly for animals; for people it can sound rude. |
At the Dentist: Pointing out a Sore Tooth
A patient tells a dentist which part of the mouth hurts. These lines describe the problem and a simple examination instruction; they do not name a diagnosis.
Dentist
어느 쪽 이가 아파요?
Eoneu jjok iga apayo?
Which side do your teeth hurt on?
Patient
왼쪽 어금니가 아파요.
Oenjjok eogeumniga apayo.
My left molar hurts.
Dentist
입을 벌려 주세요.
Ibeul beollyeo juseyo.
Please open your mouth.
Patient
이 이가 아파요.
I iga apayo.
This tooth hurts.
어느 쪽 asks which side, and 어금니 names a back tooth or molar. The patient can point while saying 이 이가 아파요. The first 이 means “this”, the second 이 means “tooth”, and 가 marks the tooth as the subject. Repeated syllables can be natural when each has a different job.
Where Will You Hear 이 and 치아?
At home, 이를 닦다 is the everyday phrase for brushing teeth. At a clinic, a patient can still use ordinary 이 when speaking to the dentist. The word is neutral: you do not need a technical term just because the listener is a professional. The polite ending in 이가 아파요 makes the complaint suitable for the conversation.
A dental leaflet, product label, or clinic explanation may use 치아 instead. 치아 미백 means “tooth whitening”, and 치아 교정 means “orthodontic treatment” or “straightening teeth”. The word 치아 fits these professional descriptions. It is a formal synonym, rather than a special respectful word for an older person’s teeth.
이빨 is usual for animal teeth and can sound rough when applied to people. You may hear it in jokes, arguments, or casual dialogue, but 이 is the safer neutral choice for describing your own tooth at an appointment. A drama character’s word choice can reveal tone as well as literal meaning.
Useful Tooth Phrases beyond Brushing
이가 나다 means “for a tooth to come in”. This is useful when talking about a baby’s developing teeth. 이가 빠지다 means “for a tooth to fall out”, as in the existing example. Both use 이가 because the tooth is what appears or falls out.
이를 뽑다 means “to pull out a tooth”. The object marker 를 fits because someone acts on the tooth. Compare 이가 빠지다 with 이를 뽑다: one describes the tooth coming out, and the other describes someone removing it. The grammar helps distinguish the event from the action.
이를 악물다 literally means “to clench one’s teeth”. It can also suggest bearing pain or making a determined effort. In a story, the phrase may describe resolve rather than a dental problem. Look for whether the surrounding scene concerns the mouth or the person’s determination.
How Do You Specify One Tooth or Several Teeth?
이 can mean either “tooth” or “teeth”. 이를 닦다 naturally means brushing your teeth as a routine; it does not imply cleaning just one tooth. When the exact number matters, add a number and counter: 이 한 개 means one tooth, and 이 두 개 means two teeth.
To identify the location, 앞니 means a front tooth and 어금니 means a back tooth or molar. These words help you move beyond a general 이가 아파요. You can name the side as well, as the patient does in the dialogue, or point when you do not know the more specific word.
Related Words around the Mouth
| Korean | Meaning | Useful note |
|---|---|---|
| 입 | mouth | The opening containing the teeth. |
| 잇몸 | gum | The tissue around the teeth. |
| 앞니 | front tooth | Names a tooth at the front of the mouth. |
| 어금니 | molar; back tooth | Names a tooth toward the back. |
The body vocabulary lesson teaches the wider set of body parts. Naming the gum or mouth separately makes a description clearer than using 이 for every uncomfortable area nearby.
Quick Self-Test
- In 이 이가 아파요, what does the first 이 mean?
- Which phrase describes a tooth falling out: 이가 빠지다 or 이를 뽑다?
- Does 이를 닦다 imply brushing only one tooth?
Show answers
- “This”. The next 이 is the noun “tooth”.
- 이가 빠지다. 이를 뽑다 means someone pulls the tooth out.
- No. 이 can mean tooth or teeth, and the phrase normally describes brushing your teeth.
Frequently Asked Questions
How do you say "tooth" in Korean?
Say 이 (i).
Is there a formal word for teeth?
Yes. 치아 is the formal or medical term.
Why avoid 이빨 for people?
It is casual and mostly for animals, so it can sound rude.
How do I say "brush your teeth"?
Say 이를 닦다.
Related Words and What to Learn Next
- Theme list: body word list. 이 follows the other body parts there.
- Index: Korean words A to Z.
- Compare with the dentist page. The dentist is where this word gets used most.