Let no one be enrolled as a widow under sixty years old, having been the wife of one man,
Having been the wife of one man ... This is the same word used in  1 Timothy 3:2, that the husband of one wife could be an elder; and the meaning would appear to be the same.  The past perfect is used here because the husband (by the definition of widow) would already have been dead.  The similarity of the qualification, however has led some to assert that these were the "female presbyters"!  But as Lenski said, "These women were not congregational officers, such as elders or deacons."[13]