Where does “Merlín” come from?

Merlín (Spanish) comes from Medieval Latin Merlinus, from Old French Merlin, from Old Welsh Myrddin, from Proto-Indo-European mori- — marsh, lake, sea; sea.

Ancestry of “Merlín”, step by step

Step	Language	Word	Meaning
1	Medieval Latin	Merlinus	—
2	Old French	Merlin	—
3	Old Welsh	Myrddin	—
4	Proto-Indo-European	mori-	marsh, lake, sea; sea

Every word from Proto-Indo-European mori- →

Merlín — Etymology, Origin & Word History | Etymology Explorer