This is the 763rd most frequent Korean word.
것이고
"것이고" is a grammatical construction meaning "and it is a thing that" or "and it is."
It is used as a connective form, combining two related ideas with "것이고" functioning as "is a part of... (and)."
이것은 내 숙제의 일부분인 것이고, 나머지는 나중에 제출할 것이다.
This is a part of my homework, and the rest I will submit later.
The word "것이고" is used to relate an individual's desire to the resulting action of helping.
네가 원하는 것이고, 나는 너를 도와줄게.
It's what you want, and I will help you.
Here, "것이고" ties an achieved result to its impact on feelings of pride.