~로/으로

This particle is added to nouns.

  • ~로 is added to words ending in a vowel and also to those ending in ㄹ (for the ease of pronunciation).
  • ~으로 is added to words ending in a consonant (except for ㄹ).

There are 7 ways you can use it:

  1. By means of, by, with
  2. To, toward
  3. Language
  4. A choice among many options
  5. To indicate transformation or change
  6. To express a cause or reason for a result
  7. To express the order in which something happened

1. By means of, by, with

  • 저는 펜으로 서명했어요. / I signed with a pen.
  • 학생은 학교에 자전거로 갔어요. / The student went to the school by bike.
  • 저는 그 의자를 손으로 만들었어요. / I made that chair by hand.

2. To, toward

  • 오른쪽으로 오세요. / Come towards the right side.

3. Language

  • 저는 중국어로 말했어요. / I said it (or spoke) in Chinese.

4. A choice among many options (example: ice cream flavors)

Waiter: 무슨 맛으로 드릴까요? / What flavor would you like?

Guest: 딸기 맛으로 주세요. / Give me strawberry flavor please.

5. Transformation or change

  • 비가 눈으로 변했어요. / The rain changed into snow.
  • 탐이 부장님으로 고용됐어요. / Tom was hired as the manager.
  • 혜란이가 예쁜 여자로 자랐어요. / Hyeran grew up to be a pretty woman.

6. To express the cause or reason for a result

  • 김연아가 올림픽으로 유명해 졌어요. / Kim Yuna became famous because of the Olympics.

7. To express the order in which something happened.

  • 저는 첫 번째로 먹을 거예요. / I will eat first.

Source: https://www.helloinkorean.com/discover-the-7-usages-of-%EC%9C%BC%EB%A1%9C-in-korean/