불행 중 다행 [ bulhaeng jung dahaeng ]
불행 means ‘misfortune’ or ‘bad luck’. In dictionaries, 다행 is ‘good luck’ or ‘fortune’ but I think it is a little inexact. Also, for ‘good luck’ or ‘fortune’, 행운 is usually used. The meaning of 다행 can be explained better with its adverb, 다행으로 or 다행히, which means ‘fortunately’, or ‘thankfully’.
Let’s say there had been an accident and some people had been injured, but thankfully no one had died. In that kind of situations, Koreans say 불행 중 다행.
A) 어제 가방을 잃어버렸어. (I lost my bag yesterday.) 그런데 폰은 다행히 찾았어. (Luckily, I found my phone.) B) 불행 중 다행이다.
A) 000에서 지진이 있었는데, 사상자는 없었대. (I heard there was an earthquake in 000 but there are no casualties.) B) 불행 중 다행입니다.