Trend
A persistent directional move. Up = HH + HL. Down = LH + LL.
Trends define your bias. Trading against the higher-TF trend on the lower TF requires exceptional timing and usually costs money. Most retail losses come from trying to pick tops and bottoms.
Learn to actually use Trend.
Definitions are the easy part. The free first five modules put this on a real chart and make you do the work. No card required.