Etymon
gem-under-protowest-germanic-undar-old-english-under-middle-english-under-english-under-protoindoeuropean-h2ed-protoitalic-ad-protoitalic-ad-latin-ad-protoindoeuropean-ke-protoindoeuropean-kom-protoitalic-kom-protoitalic-kom-latin-com-protoindoeuropean-med-protoindoeuropean-os-protoitalic-medos-latin-modus-latin-commodusnom
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.