77%RatingSave Gender Feminine & Masculine Usage English (Modern) Pronounced Pron. KAS-i-dee [key·IPA] Meaning & HistoryExpand Links From an Irish surname (Anglicized from Irish Gaelic Ó Caiside), which is derived from the byname Caiside. Very rare as a given name before the 1970s, it established itself in the 80s and then surged in popularity during the 90s. Related NamesFamily Tree·Details VariantKassidyDiminutivesCass, Cassie, Cassy PopularityDetails Last ranked #97 in 2004 Canada Last ranked #476 in 2021 (f) #987 in 1992 (m) United States People think this name isRate·Details youthful natural wholesome refined strange Categories male to female, modern English, Pokemon characters, Sims 3 characters, surnames, trendy, WITCH characters, y vowels