Where does “długopłetwiec” come from?

długopłetwiec (Polish) comes from Polish płetwa, from Old Polish plutwa, from Old Czech plútva, from Old Czech plúti, from Proto-Slavic pluti, from Proto-Balto-Slavic plauˀtei, from Proto-Indo-European pleh₃(w)- — to swim, flow.

długopłetwiec (Polish): humpback whale

Definitions

humpback whale

Ancestry of “długopłetwiec”, step by step

długopłetwiec traces back through two separate lines of ancestry.

via Polish płetwa

Step	Language	Word	Meaning
1	Polish	płetwa	fin, flipper; swim fin
2	Old Polish	plutwa	fin
3	Old Czech	plútva	fin
4	Old Czech	plúti	to sail, to float, to flow
5	Proto-Slavic	pluti	to swim; to sail
6	Proto-Balto-Slavic	plauˀtei	to swim
7	Proto-Indo-European	pleh₃(w)-	to swim, flow

via Polish długi

Step	Language	Word	Meaning
1	Polish	długi	long; nominative/accusative/vocative plural of...
2	Old Polish	długi	long
3	Proto-Slavic	dь̀lgъ	long
4	Proto-Balto-Slavic	dílˀgas	long
5	Proto-Indo-European	dl̥h₁gʰós	long

Every word from Proto-Indo-European pleh₃(w)- →Every word from Proto-Balto-Slavic plauˀtei →Every word from Proto-Slavic pluti →