A trend is the general direction of the market. But in identifying the primary trend we must account for the secondary trends as well as the daily price movements. If the irregular patterns of highs is increasing and the irregular patterns of lows is increasing then the primary trend is up; we are in a Bull Market. If the irregular pattern of highs is decreasing and the irregular pattern of lows is decreasing then the primary trend is down; we are in a Bear Market.
Sometimes the market moves sideways with successive highs and lows occurring at about the same level or going in different directions. In a sideways market technical analysts obsess about every successive high and low, waiting for the first clear indicator of the next trend; with it be up or down? This is where resistance and support lines come in.