Where does “ffyrnic” come from?

ffyrnic (Middle Welsh) comes from Proto-Brythonic *förnɨg, from Latin fornix, from Latin furnus, from Proto-Italic fornos, from Proto-Indo-European gʷʰr̥-nós, from Indo-European *gʷʰer-.

Ancestry of “ffyrnic”, step by step

Step	Language	Word	Meaning
1	Proto-Brythonic	*förnɨg	—
2	Latin	fornix	arch, vault; brothel
3	Latin	furnus	oven; bakery
4	Proto-Italic	fornos	—
5	Proto-Indo-European	gʷʰr̥-nós	—
6	Indo-European	*gʷʰer-	—

Words derived from “ffyrnic”

ffyrnig

Every word from Indo-European *gʷʰer- →Every word from Proto-Indo-European gʷʰr̥-nós →Every word from Proto-Italic fornos →