Reversal

What Does Reversal Mean?
A change in the direction of a price trend. On a price chart, reversals undergo a recognizable change in the price structure. An uptrend, which is a series of higher highs and higher lows, reverses into a downtrend by changing to a series of lower highs and lower lows. A downtrend, which is a series of lower highs and lower lows, reverses into an uptrend by changing to a series of higher highs and higher lows. 

Also referred to as a "trend reversal", "rally" or "correction".

Investopedia explains Reversal
A reversal can be a positive or negative change against the prevailing trend. Technical analysts watch for these patterns because they can indicate the need for a different trading strategy on the same security.

For example, if a technical analyst holds stock ABC and notices a reversal pattern, he or she may want to consider closing his or her existing long position and assuming a short position to capitalize on the potential downward movement of the stock's price.