Key Facts
- Word: 사이 (sai)
- Part of speech: noun (location word); origin: native Korean
- Meaning: between, gap / interval, relationship
- Register: neutral; often follows a pair, as in 은행과 우체국 사이
Between in Korean: Meaning and Register
사이 has three senses: between, a gap or interval, and a relationship. It is a native, neutral location word that often follows a pair, as in 은행과 우체국 사이. The relationship sense is the surprising one, because it uses the same noun for space and for the bond between people.
Pronunciation
RR sai, two syllables: sa-i, not the single English sound of "sigh". With 에 it becomes sa-i-e, with 로 sa-i-ro, and with 예요 sa-i-ye-yo, all shown in the examples.
Example Sentences
은행과 우체국 사이에 있어요.
Eunhaenggwa ucheguk saie isseoyo.
It is between the bank and the post office.
은행과 우체국 사이에 있어요 puts two landmarks before 사이. The particle 과 links them and 에 gives the location.
우리는 친한 사이예요.
Urineun chinhan saiyeyo.
We are close friends.
친한 사이예요 uses 사이 for a relationship: literally "we are a close relationship". 친한 is the form of "close" that sits before a noun.
나무 사이로 바람이 불어요.
Namu sairo barami bureoyo.
The wind blows between the trees.
나무 사이로 uses 로 for movement through a gap, so the wind passes between the trees.
Reading the Examples Together
The examples show space, relationship and movement. The first links two landmarks with 과, the second describes closeness, and the third uses 로 for passing through a gap. The words around 사이 tell you which reading you have.
Collocations
| Korean | English |
|---|---|
| 사이에 | between |
| 사이가 좋다 | to get along well |
| 둘 사이 | between the two |
사이에 is between, 사이가 좋다 is to get along well and 둘 사이 is between the two. The second one shows the relationship sense, with 가 marking the subject.
Common Mistake
Learners follow English word order.
Wrong: 학교 사이 우체국 for "between the school and the post office".
Correct: 학교와 우체국 사이에. Both items come first, joined by 와 (or 과 after a consonant), and 사이에 closes the phrase.
사이 vs 가운데
| Word | Meaning | Note |
|---|---|---|
| 사이 | between, gap / interval, relationship | This page's word: the space between two points |
| 가운데 | middle | 가운데 is the center of a space; 사이 is the space between two points. |
| 옆 | beside | 옆 is next to something. |
가운데 is the centre of a space, while 사이 is the space between two points. 옆 is next to one thing. A bank next to the post office is 우체국 옆; a bank with the post office on one side and the school on the other is 학교와 우체국 사이.
Finding a Cafe Entrance
A friend gives two landmarks for a small cafe. The entrance is in the gap between the buildings.
Friend A
카페가 어디에 있어요?
Kapega eodie isseoyo?
Where is the cafe?
Friend B
은행과 약국 사이에 있어요.
Eunhaenggwa yakguk saie isseoyo.
It is between the bank and the pharmacy.
Friend A
입구도 두 건물 사이에 있어요?
Ipgudo du geonmul saie isseoyo?
Is the entrance between the two buildings too?
Friend B
네. 그 사이로 들어오세요.
Ne. Geu sairo deureooseyo.
Yes. Come in through that gap.
은행과 약국 gives the two landmarks before 사이. 두 건물 means “two buildings”, referring back to them. 그 사이로 changes the phrase from a location to a route through the gap. 들어오세요 invites the listener to come in toward the speaker.
What If the Sentence Names More than Two Things?
나무 사이 means between or among trees. Korean does not need a separate word matching the English choice between “between” and “among” here. The gaps are understood from the group of trees. Likewise, 사람들 사이 means among people, with the plural group supplying the reference points.
사이 also leaves room for unequal distances. A cafe between a bank and a pharmacy need not be exactly halfway from each. 가운데 focuses on the middle or centre, while 사이 identifies the intervening space. To find a small entrance, two landmarks can be more useful than a general instruction to look in the middle.
Relationship Phrases You Will Hear in Conversations
사이가 좋다 literally means “the relationship is good” and naturally means getting along well. 사이가 나쁘다 is its negative counterpart: people do not get along. These describe how people relate to one another rather than how far apart they stand.
무슨 사이예요 asks “what is your relationship?” In a drama, a character may ask this after seeing two people together. The question can sound personal because it asks how the people are connected. 친한 사이 means a close relationship, but it does not by itself identify the people as a romantic couple. Look for the answer or the scene to supply that detail.
둘 사이 means “between the two” or “the relationship between the two”. A phrase about distance points toward space; a phrase about a disagreement points toward their relationship. The noun keeps its basic idea of a connection or interval while the surrounding words select the sense.
A Time Expression with 사이
눈 깜짝할 사이 means “in the blink of an eye”. Literally, it is the interval in which an eye blinks; in use, it means a very short moment. You may hear it in storytelling when something disappears or happens surprisingly fast. The Korean Basic Dictionary lists it as an idiom for a very short moment, rather than a measurement of time.
| Korean | Meaning | Useful note |
|---|---|---|
| 틈 | gap / opening | Focuses on an opening rather than a relationship. |
| 가운데 | middle / centre | Useful when the central position matters. |
| 관계 | relationship / connection | A broader word for how people or things are connected. |
| 약국 | pharmacy | A useful landmark to pair with 은행 in directions. |
See the directions and position lesson for the spatial uses of 사이 alongside 옆 and 가운데. Relationship phrases need their own context even though they use the same familiar noun.
Quick Self-Test
- Must a cafe described with 사이 be exactly halfway between its landmarks?
- Does 친한 사이 automatically mean a romantic couple?
- What does 눈 깜짝할 사이 mean in a story?
Show answers
- No. 사이 identifies the intervening space, not an exact midpoint.
- No. It says the people are close; context explains their connection.
- In the blink of an eye: very quickly or within a brief moment.
FAQ
What Is the Pattern for between a and B?
Say A와 B 사이에, as in 학교와 우체국 사이에. Use 와 after a vowel and 과 after a consonant, so 은행과 우체국 사이에 starts with 과.
Can 사이 Describe a Relationship?
Yes. 우리는 친한 사이예요 means we are close friends. 사이가 좋다 means two people get along well, so the word for a gap in space also names the bond between people.
How Is 사이 Different from 가운데?
가운데 is the centre of a space, such as the middle of a room. 사이 names the intervening space between reference points. The reference can also be a group, as in 나무 사이, between or among trees.
What Does 사이가 좋다 Mean?
사이가 좋다 means to get along well, literally "the relationship is good". 가 marks 사이 as the subject, and 좋다 is the adjective "good".
Keep Learning
- Theme list: Korean Directions Vocabulary, where 사이 sits alongside related words.
- Index: Korean words A to Z
- Practice: vocabulary flashcard decks include 사이.