Etymon
enm-marchaunt-english-merchant-protoindoeuropean-ter-protoindoeuropean-dhlom-protoindoeuropean-dhlis-protoitalic-lis-latin-bilis-latin-abilis-protoindoeuropean-teh2-protoindoeuropean-ts-protoindoeuropean-teh2ts-protoitalic-tats-latin-tas-latin-abilitas-middle-french-abletebor
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.