I was looking up the Korean word for “together”, when I came across its entry in the pure Korean dictionary on my iPhone. There’s this big bracket which seems to provide the etymology of the word.
I recognise some Hanja; they possibly refer to old Korean texts which made use of this word. I also see a few obsolete hangul symbols, meaning that some Middle Korean is written in there too. However, I am a beginner in Korean and do not understand the meaning of the text.
What information does the bracket convey? In particular, what does the “square root” indicate?