英语词源字典 - 在线词源网站

irrelevance (n.)[irrelevance 词源字典]: 1735, from irrelevant + -ance. Earlier in the same sense was irrelevancy (1590s).[irrelevance etymology, irrelevance origin, 英语词源]
relevance (n.): 1733; see relevant + -ance. Related: Relevancy (1560s).