Etymon
pie-ne-protogermanic-ne-protoindoeuropean-is-protoindoeuropean-h1oynos-protogermanic-ainaz-protogermanic-nainaz-protowest-germanic-nain-old-english-nan-middle-english-non-old-english-nan-old-english-nan-middle-english-non-english-non-protoindoeuropean-h2ed-protoitalic-ad-protoitalic-ad-latin-ad-protoitalic-kaussa-old-latin-caussa-latin-causa-protoindoeuropean-h2-protoindoeuropean-eh2-protoindoeuropean-yeti-protoindoeuropean-eh2yeti-protoitalic-ao-latin-o-latin-accuso-protoindoeuropean-wos-protoindoeuropean-ihwosder
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.