Where does “atúaid” come from?

atúaid (Middle Irish) comes from Old Irish antúaid, from Old Irish an-, from Proto-Celtic an-, from Proto-Indo-European n̥-, from Proto-Indo-European ne — not.

Ancestry of “atúaid”, step by step

Step	Language	Word	Meaning
1	Old Irish	antúaid	from the north
2	Old Irish	an-	un-, not; very
3	Proto-Celtic	an-	un-, not
4	Proto-Indo-European	n̥-	not, un-
5	Proto-Indo-European	ne	not

Words derived from “atúaid”

a tuath

Every word from Proto-Indo-European ne →Every word from Proto-Indo-European n̥- →Every word from Old Irish an- →