What is a trend?

Price does not travel in a straight line; it moves in waves. The top of each wave is called a swing high, the bottom a swing low. A trend is the overall direction you read from how these highs and lows line up.

In an uptrend every new high is higher than the last, and every new low is higher too — in short, "higher highs, higher lows". A downtrend is the mirror image: lower highs and lower lows. The beauty of this definition is that it rests on countable points, not on gut feeling; two people can look at the same chart and mark the same swings.

What a trend does not tell you is how long it will last. The saying "the trend is your friend" describes a tendency to continue; it is not a promise of continuation. Every trend ends eventually, and you only see that it has ended when the sequence of highs and lows breaks. Nor does it tell you which timeframe you are reading it on: the same chart can be printing lower highs on the hourly while the daily sequence is still rising.