Where does “Inis Faithlinn” come from?

Inis Faithlinn (Irish) comes from Irish inis, from Middle Irish indisid, from Old Irish indisin, from Old Irish in·fét, from Proto-Celtic *weideti, from Proto-Indo-European weyd- — to see.

Ancestry of “Inis Faithlinn”, step by step

Step	Language	Word	Meaning
1	Irish	inis	island; tell, relate
2	Middle Irish	indisid	tells, recounts, mentions, describes
3	Old Irish	indisin	—
4	Old Irish	in·fét	—
5	Proto-Celtic	*weideti	to tell, relate
6	Proto-Indo-European	weyd-	to see

Every word from Proto-Indo-European weyd- →Every word from Proto-Celtic *weideti →Every word from Old Irish in·fét →