Trend
A directional price move: an uptrend prints higher highs and higher lows, a downtrend the reverse. Identifying the trend starts technical analysis.
Definition
A trend is a directional price move: in an uptrend a sequence of higher highs and higher lows (HH/HL), in a downtrend lower highs and lower lows (LH/LL). The definition has to be measurable in your playbook (timeframe, rules for a break of structure); without that, “trend” is just an opinion.
Example
On the D1 chart successive swing highs and swing lows keep rising. You plan longs from pullbacks according to your rule, not shorts “because RSI is overbought”. Invalidation: a break of the most recent HL as defined by your own criteria.
Anti-example / common mistake
Drawing a trend after two candles on the M5 chart and building a weekly bias on it. Or fighting a higher-timeframe trend with setups from a lower timeframe and no plan.
Verifiable sources
The concept of a trend (higher highs and lows, the trend line, the primary/secondary/minor classification) comes from the classic Edwards & Magee, “Technical Analysis of Stock Trends” (1948) — the most frequently cited source for this terminology. Modern material (the CMT Association, for example, and analytical curricula) formalises the definitions of swing highs and lows. The interpretation is heuristic rather than a law of physics — hence the note about making it measurable in your playbook.