Etymon
enm-marchaunt-english-merchant-protoindoeuropean-iskos-protogermanic-iskaz-protowest-germanic-isk-old-english-isc-middle-english-ish-english-ish-english-merchantish-from-merchant-ish
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.