Diworsification

The process of adding to one's portfolio in such a way that the risk/return tradeoff is worsened.

Investopedia Says:
Investors often achieve this by investing in a number of different mutual funds that have similar investment strategies within the same grouping of shares. 

A diversification strategy usually involves the accumulation of assets with negative correlations, which reduces risk and can increase potential returns by minimizing the negative effect of any one asset on portfolio performance. However, investing in too many assets with similar correlations will result in an averaging effect where risk is at its lowest level and additional assets reduce potential portfolio returns as well as the chances of outperforming a benchmark.

Related Links:
Reducing risk and increasing returns in your portfolio is all about finding the right balance. Introduction To Diversification
A diversified portfolio will protect you in a tough market. Get some solid tips here! 5 Tips For Diversifying Your Portfolio
Without this risk-reduction technique, your chance of loss will be unnecessarily high. The Importance Of Diversification
This investment is very popular, but that doesn't mean it comes without risk. Mutual Funds Are Awesome - Except When They're Not
If you diversify too much, you might not lose much, but you won't gain much either. The Dangers Of Over-Diversifying Your Portfolio