Delainey is a modern spelling of Delaney, which comes from the Irish surname Ó Dubhshláine, usually explained as "descendant of the dark challenger"; some trace it instead to the Norman French de l'aunaie, "from the alder grove". The spelling with -ainey gives it the look of Lainey and Delainey can be shortened to either. In the United States Delainey has climbed from number 3793 in 2020 to number 1350 in 2024, its best rank, and stands at number 1390 in 2025.