Where does “Finlandic” come from?

Finlandic (English) comes from English Finland, from Old Norse Finnland, from Old Norse land, from Proto-Germanic landą, from Proto-Indo-European lendʰ- — land, heath; loins.

Ancestry of “Finlandic”, step by step

Finlandic traces back through two separate lines of ancestry.

via English Finland

StepLanguageWordMeaning
1EnglishFinland
2Old NorseFinnland
3Old Norselandland
4Proto-Germaniclandąland, area of ground
5Proto-Indo-Europeanlendʰ-land, heath; loins

via English ic

StepLanguageWordMeaning
1Englishicrelated or pertaining to; having the character of
Every word from Proto-Indo-European lendʰ-Every word from Proto-Germanic landąEvery word from Old Norse land