Where does “Cúige Mumhan” come from?

Cúige Mumhan (Irish) comes from Old Irish Cóiced Muman, from Old Irish cóiced, from Proto-Celtic kʷenkʷetos — fifth.

Ancestry of “Cúige Mumhan”, step by step

StepLanguageWordMeaning
1Old IrishCóiced Muman—
2Old Irishcóicedfifth; province
3Proto-Celtickʷenkʷetosfifth
Every word from Proto-Celtic kʷenkʷetos →Every word from Old Irish cóiced →Every word from Old Irish Cóiced Muman →