I would think that generally one means different things. Specifically, a diversified portfolio would hold stocks and bonds. Or, if one is of the "stocks don't

I would think that generally one means different things. Specifically, a diversified portfolio would hold stocks and bonds. Or, if one is of the "stocks don't go up over the long term" persuasion, it means stocks + shorts (for a net market neutral portfolio) and bonds. So no, popular index funds are not diversified. There are exceptions, of course.