Where does “antidown” come from?

antidown (English) comes from English Down, from Middle English doun, from Old English dūn, from Proto-Germanic *dūnā, from Proto-Celtic dūnom, from Proto-Indo-European dʰewh₂- — smoke; mist, haze.

antidown (English): Being or relating to an anti-down quark

Definitions

Being or relating to an anti-down quark

Ancestry of “antidown”, step by step

antidown traces back through two separate lines of ancestry.

via English Down

Step	Language	Word	Meaning
1	English	Down	usually known as County Down
2	Middle English	doun	down
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 English anti

Step	Language	Word	Meaning
1	English	anti	Opposed to something; That has a torsion angle...
2	English	anti-	Against, hostile to; Contrasting with the norm;...
3	Ancient Greek	ἀντι-	anti-, against; like, reminiscent of
4	Ancient Greek	ᾰ̓ντῐ́	opposite

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