Where does “프라하” come from?

프라하 (Korean) comes from Czech Praha, from Czech práh, from Old Czech práh, from Proto-Slavic porgъ, from Proto-Balto-Slavic parˀgas, from Proto-Indo-European porg-o-.

Ancestry of “프라하”, step by step

Step	Language	Word	Meaning
1	Czech	Praha	—
2	Czech	práh	doorstep
3	Old Czech	práh	threshold
4	Proto-Slavic	porgъ	threshold, doorstep
5	Proto-Balto-Slavic	parˀgas	—
6	Proto-Indo-European	porg-o-	—

Every word from Proto-Indo-European porg-o- →Every word from Proto-Balto-Slavic parˀgas →Every word from Proto-Slavic porgъ →