Where does “brēdan” come from?

brēdan (Old English) comes from Proto-Germanic brōdijaną, from Proto-Indo-European bʰreh₁- — warm; breath, mist, vapour, steam.

Ancestry of “brēdan”, step by step

Step	Language	Word	Meaning
1	Proto-Germanic	brōdijaną	To keep warm; brood; To breed
2	Proto-Indo-European	bʰreh₁-	warm; breath, mist, vapour, steam

brēdan — Etymology, Origin & Word History | Etymology Explorer