Where does “knallrød” come from?

knallrød (Norwegian Bokmål) comes from Norwegian Bokmål rød, from Old Norse rauðr, from Old English dūn, from Proto-Germanic *dūnā, from Proto-Celtic dūnom, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.

knallrød (Norwegian Bokmål): bright red, scarlet

Definitions

bright red, scarlet

Ancestry of “knallrød”, step by step

knallrød traces back through two separate lines of ancestry.

via Norwegian Bokmål rød

Step	Language	Word	Meaning
1	Norwegian Bokmål	rød	red
2	Old Norse	rauðr	red
3	Old English	dūn	hill, down; hill, dune; hill, mountain
4	Proto-Germanic	*dūnā	—
5	Proto-Celtic	dūnom	stronghold, rampart
6	Proto-Indo-European	dʰewh₂-	smoke; mist, haze

via Norwegian Bokmål knall

Step	Language	Word	Meaning
1	Norwegian Bokmål	knall	bang, crack, detonation, explosion; !; great!...
2	Norwegian Bokmål	knalle	—

Every word from Proto-Indo-European dʰewh₂- →Every word from Proto-Celtic dūnom →Every word from Proto-Germanic *dūnā →