Where does “eitek” come from?

eitek (Breton) comes from Breton eizh, from Middle Breton eiz, from Old Breton eith, from Proto-Brythonic üiθ, from Proto-Celtic oxtū, from Proto-Indo-European oḱtṓw, from Proto-Indo-European aḱ- — sharp, pointed; sharp, pointed, edgy; sharp,...

eitek (Breton): eighteen

Definitions

eighteen

Ancestry of “eitek”, step by step

eitek traces back through two separate lines of ancestry.

via Breton eizh

Step	Language	Word	Meaning
1	Breton	eizh	eight
2	Middle Breton	eiz	—
3	Old Breton	eith	—
4	Proto-Brythonic	üiθ	eight
5	Proto-Celtic	oxtū	eight
6	Proto-Indo-European	oḱtṓw	eight
7	Proto-Indo-European	aḱ-	sharp, pointed; sharp, pointed, edgy; sharp,...

via Breton dek

Step	Language	Word	Meaning
1	Breton	dek	ten
2	Middle Breton	dek	—
3	Old Breton	dec	—
4	Proto-Brythonic	deg	ten
5	Proto-Celtic	dekam	ten
6	Proto-Indo-European	déḱm̥	ten

Every word from Proto-Indo-European aḱ- →Every word from Proto-Indo-European oḱtṓw →Every word from Proto-Celtic oxtū →