This is the 10078th most frequent Korean word.
공화국이었던
"That was a republic."
Here, '공화국이었던' is used to describe a country that was formerly a republic in the context of its history.
그 나라는 한때 공화국이었던 때가 있었다.
That country once experienced a time when it was a republic.
In this sentence, '공화국이었던' is employed to specify a state referred to previously as a former republic.
그가 말한 공화국이었던 국가의 이름은 무엇인가요?
What is the name of the country that he mentioned as being a former republic?
'공화국이었던' in this context refers to the era or time period when a particular country was a republic.