I talk often about "reclaiming the 20-day EMA". I simply mean trading back above the 20-day EMA. An uptrend typically is comprised of higher highs and higher lows, with the 20-day EMA acting as key support. Then the rise will eventually run out of momentum, printing a negative divergence. That can start a downtrend. To give
you an example, let's look at the current chart of DexCom Inc. (DXCM):