Etymon
pie-oktow-protogermanic-ahtou-protowest-germanic-ahto-old-english-eahta-middle-english-eighte-english-eight-english-some-english-eightsome-from-eight-some
A dedicated page for this root is on the way — it will gather every word descended from it, sibling forms across daughter languages, and a branching map of the family tree.