원인(won-in, wonin)
The reason or cause that makes something happen
When to use
starting reason of event, problem cause analysis, scientific cause identification
The nuance
Use 원인 to indicate the fundamental reason why an event or phenomenon occurs. It is often used in the form ‘~의 원인이다’ and should not be confused with 결과 or 과정.
과정(gwa-jeong, gwajeong)
The stages or method by which something progresses
When to use
work progress stages, learning method explanation, flow of change
The nuance
Use 과정 to describe the flow or stages between the start and end of something. It sits between 원인 and 결과 and is used in expressions like ‘과정을 거치다’.
결과(gyeol-gwa, gyeolgwa)
The final state or effect of an action or event
When to use
exam results, project completion, effect of actions
The nuance
Use 결과 to refer to the final state after an event or action has finished. It is used in the form ‘~의 결과이다’ and unlike 원인 or 과정, it indicates the finished state.