Meaning A boy's name of Irish origin, it means "of the tree field." Origin of Alasdair Celtic , Irish Popular Middle Names Lachlan Pronunciation 🔊 Listen Alasdair Similar Names Mac Ailean Dud Abracham Tchad Cearbhall Aralt Fachnan Fahey Rearden Reidhachadh Year by Year Popularity of Alasdair