Etymon
enm-counter-english-counter-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-accusarelbor
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.