Etymology tree
Latin Rōma
Proto-Indo-European *-nós
Proto-Italic *-nos
Latin -nus
Latin -ānus
Latin rōmāna
Arabic رُمَّانَة (rummāna)influ.
Old Galician-Portuguese romãa
Portuguese romã
Inherited from Old Galician-Portuguese romãa, and in the sense of pomegranate a phono-semantic matching of Arabic رُمَّانَة (rummāna, “pomegranate”) parsed as Latin rōmāna (“Roman”).