1. (Anc. Geog.) Of or pertaining to Miletus, a city of Asia Minor, or to its inhabitants. [ 1913 Webster ]
2. (Irish Legendary Hist.) Descended from King Milesius of Spain, whose two sons are said to have conquered Ireland about 1300 b. c.; or pertaining to the descendants of King Milesius; hence, Irish. [ 1913 Webster ]
n. 1. A stone serving the same purpose as a milepost. [ 1913 Webster ]
2. An event or accomplishment marking a significant advance in an endeavor; a notable achievment; as, putting a man in orbit was a major milestone on the way to the moon. Syn. -- milepost. [ PJC ]