In reality, there are almost an infinite number of trends interacting with one another, from the very short term trends covering minutes and hours to superlong trends lasting 50 or 100 years.
Most technicians, however, limit trend classifications to three. There is a certain amount of ambiguity, however, as to how different analysts define each trend.
Dow Theory, for example, classifies the major trend as being in effect for longer than a year. Because futures traders operate in a shorter time dimension than do stock investors, I would be inclined to shorten the major trend to anything over six months in the commodity markets.
Dow defined the intermediate, or secondary, trend as three weeks to as many months, which also appears about right for the futures markets.
The near term trend is usually defined as anything less than two or three weeks.
Each trend becomes a portion of its next larger trend. For example, the intermediate trend would be a correction in the major trend. In a long term uptrend, the market pauses to correct itself for a couple of months before resuming its upward path. That secondary correction would itself consist of shorter waves that would be identified as near term dips and rallies.