Two random variables X and Y are uncorrelated if E(XY)=E(X)E(y). Note that this does not guarantee they are independent. Source: econterms

In probability theory and statistics, to call two real-valued random variables X and Y uncorrelated means that their covariance is zero.

When investments are affected by different economic pressures, they rise or fall at different times. This lowers the risk in your portfolio, because when some of your assets lose value, others gain.

not varying together