Harmon

As an English surname, by way of Norman/Anglo-Norman/Middle English/Old French from Proto-West Germanic *hari (“army”) + *mann (“man”), similar to Herman. Also Americanized from German variants such as Harmann, Hermann. Compare Harman.

As an Irish surname, variant of Hargadon, from Ó hArgadáin (literally “descendant of Argadán”), from a diminutive of airgead (“silver”).