Examples: cartography card archaeology archetype monarchy legal loyal purse personal cinema kinase car carpenter hippopotamus Mesopotamia dative data date
...
Proto-Indo-European *h₂er-

→ English army (root)
→ English army (derived)
→ English rational (root)
→ English article (root)
→ English article (mention)
→ English arm (root)
→ English arm (mention)
→ English arm (mention)
→ English art (root)
→ English rite (root)
→ English read (root)
→ English rate (root)
→ English reason (root)
→ English reason (mention)
→ English artificial (root)
→ English ordinal (root)
→ English order (root)
→ English arthropod (root)
→ English ordinary (root)
→ English armistice (root)
→ English adorn (root)
→ English alarm (root)
→ English ornament (root)
→ English rhyme (root)
→ English rime (root)
→ English harmony (root)
→ English aristocrat (root)
→ English aristocratic (root)
→ English ready (root)
→ English artist (root)
→ English artful (root)
→ English inarticulation (root)
→ English articulate (root)
→ English harmonious (root)
→ English ratio (root)
→ English inert (root)
→ English aristocracy (root)
→ English artisan (root)
→ English artifact (root)
→ English arithmetic (root)
→ Avestan 𐬀𐬴𐬀𐬎𐬎𐬀𐬥 (compound)
→ Belarusian ярмо (root)
→ Bulgarian ярем (root)
→ Catalan arma (mention)
→ Cebuano armas (mention)
→ Czech jařmo (root)
→ Old Church Slavonic ꙗрьмъ (root)
→ Old Church Slavonic ꙗрьмъ (derived)
→ German Arm (mention)
→ Middle English armee (root)
→ Middle English armee (mention)
→ Esperanto artefakto (root)
→ Spanish arma (mention)
→ Spanish armonía (root)
→ Spanish armónico (root)
→ Estonian armee (root)
→ Estonian armee (mention)
→ Persian را (root)
→ Persian را (inherited)
→ French arme (mention)
→ French armée (root)
→ French armée (mention)
→ Middle French armee (root)
→ Middle French armee (mention)
→ Old French armee (root)
→ Old French armee (mention)
→ Irish artra- (root)
→ Ancient Greek ἄρθρον (root)
→ Ancient Greek ἁρμός (root)
→ Ancient Greek ἁρμός (mention)
→ Ancient Greek ἄρα (root)
→ Ancient Greek ἄρα (derived)
→ Ancient Greek ἁρμονία (root)
→ Ancient Greek ἁρμονία (derived)
→ Ancient Greek ἁρμόζω (root)
→ Ancient Greek ἁρμόζω (derived)
→ Ancient Greek ἀραρίσκω (root)
→ Ancient Greek ἀραρίσκω (derived)
→ Ancient Greek ἀρτύω (root)
→ Ancient Greek ἀρτύω (derived)