出典:Wiktionary
Probably a calque of a similar formation in a continental West Germanic language, such as Dutch rijkdom (“wealth”) or German Reichtum (“wealth”); equivalent to rich + -dom.
Compare Middle English richedom (“wealth, riches”), 古期英語 rīċedōm (“dominion”), Swedish rikedom (“wealth, richness”), and Icelandic ríkidómur (“riches, power”).
richdom (usually uncountable, 複数形 richdoms)