Meaning A boy's name of Gaelic origin, it means "Faithful." Origin of Diolmhain Gaelic , Irish Popular Middle Names Pronunciation 🔊 Listen Diolmhain Similar Names Dallan Donal Beagin Frannsaidh Gayner Gervin Muireach Raghallach Steaphan Kellen Year by Year Popularity of Diolmhain