Words that come from Proto-Indo-European h₃erdʰ-

400 words across 27 languages descend from Proto-Indo-European h₃erdʰ- — including orthodox, orthodoxy, arduous, unorthodox, Armagh, orthographic, arboreal, orthostatic.

See the etymology of h₃erdʰ- itself →

English (194)

Irish (61)

Italian (51)

Esperanto (23)

Latin (15)

French (14)

Ancient Greek (5)

Manx (5)

Proto-Indo-European (3)

Old Irish (3)

Galician (3)

Ido (3)

Hungarian (3)

Old Spanish (2)

Translingual (2)

Sicilian (2)

Proto-Italic (1)

Sanskrit (1)

Old Occitan (1)

Dutch (1)

Neapolitan (1)

Catalan (1)

Russian (1)

Basque (1)

Venetian (1)

Greek (1)

Dalmatian (1)