Where does “Fuscus” come from?

Fuscus (Latin) comes from Latin fuscus, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.

Ancestry of “Fuscus”, step by step

Step	Language	Word	Meaning
1	Latin	fuscus	dark, dim, dimly lit; black, brown; husky, hoarse
2	Proto-Indo-European	dʰewh₂-	smoke; mist, haze