Here are some related sets of words. Except for 갔다 오다 and 왔다 가다, all are unique words so you can look up example sentences in the dictionary. - 갔다 오다: make a run to some place (and be back at one's place) - 왔다 가다: (a third person) drops by one's place (and is gone now). * 저는 시내에 (나)갔다 올게요: I'll make a run to the downtown real quick. * 시어머니가 오셨다 가셨어: My mother-in-law came by (and left). - 다녀오다: (about the same as 갔다 오다) - 다녀가다: (about the same as 왔다 가다) * 2주간 출장을 다녀왔어: I just came back from a two week business trip. * 사무실에 소방 요원이 다녀갔어: A fire officer came by the office. - 돌아오다: come back. (also means "come around" - "Another winter came around") - 돌아가다: go back. (also means "is working/operating", "is moving along", etc. - "공장이 잘 돌아간다"). * 없어졌던 고양이가 돌아왔다: Our cat that went missing has come back. * 자정까지는 서울로 돌아가야 해: I must be back in Seoul by midnight. - 데려오다: fetch someone. - 데려가다: take someone along. * 가서 의사를 데려왔다: I went and fetched a doctor. * 그 사람들은 도와달라고 아들을 데려갔다: They took my son along to get help.

"갔다 오다" and "다녀오다" are very similar words. "돌아오다" is somewhat different from both words. "돌아오다" means "return, come back" or "make a detour" "다녀오다" is originated from "다니다" "다니다" means "go somewhere regularly" "갔다 오다" is originated from "가다" 가다 means "go" "갔다 오다" can be used for general meaning of "go and get back, go and come back, be back" "다녀오다" is commonly used for some familiar place like school, workplace or house. ex) I have just been to the library. 지금 도서관에 갔다 오는 길이야. (The library is not familiar to me.) 지금 도서관에 다녀오는 길이야. (The library is familiar to me. I used to go to the library.)

갔다 오다 and 다녀 오다 seem to be same meaning. Going somewhere and coming back. Usually it is used as a past tense. For example 학교 갔다왔어요 학교 다녀왔어요 돌아오다 means " return from somewhere." It doesn't imply "we went somewhere". 학교에서 돌아왔어요 But I agree it is hard to differentiate them.