a Celtic term, denoting a hill or eminence, and which often concurs to form the names of towns, to signify their high situation, places of strength or citadels, hills or eminences, being adapted to such structures. See Dunum.

Dunum (Ptolemy), a town of Ireland; now thought to be Down or Down-Patrick, in the county of Down. W. Long. 5° 57'. N. Lat. 54° 23'.