아/어서 (a/eoseo) means "because, and then".
Links two clauses as cause-and-effect, or as a connected sequence of actions.
Checked against the official learner dictionary from the National Institute of Korean Language
- Stems with ㅏ or ㅗ take 아서 aseo, others take 어서 eoseo, and 하다 hada becomes 해서 haeseo.
- After a noun: 이라서 iraseo after a consonant, 라서 raseo after a vowel.
Build it
When to use it
Reason
Why something happened.
And then, there
The second action builds on the first.
Thanks and feelings
Set phrases like 만나서 반가워요 mannaseo bangawoyo.
Watch out
No past tense before 서 seo. The last verb carries it.
A reason with 서 seo can't come before a command. Use 니까 nikka.
In context
9 examples- 1
늦어서 죄송합니다.
Neujeoseo joesonghamnida.
I'm sorry for being late.
- 2
친구를 만나서 영화를 봤어요.
Chingureul mannaseo yeonghwareul bwasseoyo.
I met my friend and (then) we watched a movie.
- 3
값이 비싸서 안 샀어요.
Gapsi bissaseo an sasseoyo.
I didn't buy it because it was expensive.
- 4
감기에 걸려서 학교에 못 갔어요.
Gamgie geollyeoseo hakgyoe mot gasseoyo.
I caught a cold, so I couldn't go to school.
- 5
늦게 일어나서 아침을 못 먹었어.
Neutge ireonaseo achimeul mot meogeosseo.
I got up late, so I didn't get to eat breakfast.
- 6
여기 앉아서 잠깐 기다려 주세요.
Yeogi anjaseo jamkkan gidaryeo juseyo.
Please have a seat here and wait a moment.
- 7
너무 피곤해서 아무것도 하기 싫어요.
Neomu pigonhaeseo amugeotdo hagi sireoyo.
I'm so tired I don't feel like doing anything.
- 8
마트에 가서 우유 좀 사 올게.
Mateue gaseo uyu jom sa olge.
I'll go to the store and pick up some milk.
- 9
오늘 만나서 정말 반가웠어요.
Oneul mannaseo jeongmal bangawosseoyo.
It was really nice meeting you today.
Practice
8 questions가다 + 아/어서
아/어서 vs 고: linked or just listed
In the "and then" meaning, 서 seo says the two actions belong together: same place, same person, or the second uses the result of the first. 고 go just lists them.
- 친구를 만나서 영화를 봤어요. chingureul mannaseo yeonghwareul bwasseoyo "I met my friend and we saw a movie together."
- 친구를 만나고 영화를 봤어요. chingureul mannago yeonghwareul bwasseoyo "I met my friend, and then I saw a movie." Maybe on your own.
That's also why commands are fine in this meaning: 앉아서 기다리세요 anjaseo gidariseyo, "sit and wait", is a sequence, not a reason.
With nouns: (이)라서
After a noun, the reason form is 이라서 iraseo or 라서 raseo. It's very common for "because it's…":
- 주말이라서 사람이 많아요. jumariraseo sarami manayo "It's crowded because it's the weekend."
- 친구라서 믿었어요. chinguraseo mideosseoyo "I trusted him because he was my friend."
For how this compares with the other "because", see 아/어서 vs (으)니까.
Compare with similar particles
Hanja in this lesson
Words from the examples that are written with Chinese characters. Tap a character to see its page.
Use it with
- Korean sentence connectors 그래서 (geuraeseo), 하지만 (hajiman) and the rest: the words that join two sentences, next to the ending that does the same job inside one.
- Korean irregular verbs Endings that start with 아/어 (a/eo) change some verbs, so 듣다 (deutda, to listen) becomes 들어서 (deureoseo). The list shows which verbs do it.
Look it up in the dictionary
The entry for 아 in two trusted Korean dictionaries.
