It is somekind of a surname. When there was more than one person on the same area with the same last name they used a surname like Brown (Lebrun) to differenciate them. So one was called by his last name and the other by his surname. I suppose that the other had something brown. My ancestor was called Pierre Balan dit Lacombe because he came from a place with many little valley called COOMB (combe). His children took the name Lacombe afterwards. Normand Lacombe of Laval, Quebec.