Bruce, Most placenames in Ireland have their origins in Irish, and The Placenames Dept. of Queen's University states that Comber ( Down/Derry) is an English spelling of Cummar- ie Confluence. The word Cumar/Cummar in Irish definitely means a confluence. By the way, my surname has nothing to do with this- as it is a bad translation of Ó Ciaráin ( the original Irish version) which should mean 'black-haired one' Ciar means black and, but cíor means comb- hence the confusion.