'Market Trends' is explained in detail and with examples in the Economics edition of the Herold Financial Dictionary, which you can get from Amazon in Ebook or Paperback edition.
Market trends refer to the idea that financial markets tend to move in a given direction. Among the different types of these trends are secular, primary, and secondary kinds. Secular ones refer to longer time periods. Primary trends are those which happen over medium time frames. Secondary trends turn out to be those that occur over shorter time frames.
Traders try to figure out and predict such trends with the study of technical analysis. This study provides a means of characterizing such trends in the market as predictable patterns, especially when prices reach resistance and support levels, which vary with time. The dilemma with predicting trends is that they are only truly knowable after they have begun. This is because future prices can never be fully predicted with accuracy.
Secular markets actually cover those longer term trends which run from five to 25 years in duration. They are made up of a group of primary market trends. This means that a secular bull market would be comprised of bigger bull markets and smaller intervening bear markets. Conversely, secular bear markets are comprised of bigger bear markets and smaller intervening bull markets.
An example of a secular bull market was the period in U.S. markets from 1983 through 2000 (or sometimes considered to be through 2007). The intervening bear trends would be considered the Black Monday Crash in 1987 and the dot-com crash from 2000 to 2002.
Primary market trends are those which instead last only a year to several years. They generally enjoy significant and broad based support in the whole market while they are happening. In a primary bull market, the prices are generally rising. The bull market begins with a great deal of pessimism which is nearly universal. Somehow the despondency gives way to first hope, then belief before finally peaking out at irrational exuberance. At that point, the bull market has finished.
The average bull market has lasted around 8.5 years, according to the market data Morningstar compiled from 1926 through 2014. Annual gains in these types of markets averaged between 14.9 percent and 34.1 percent. Important bull markets in the U.S. occurred from 1925-1929, from 1953-1957, and from 1993-1997. Two of the three ended badly in the Great Depression and the Dotcom crash, an ominous warning to investors.
In primary bear market trends, the markets are deteriorating over a given amount of time. Vanguard defines these as minimally twenty percent price declines in a given two month period. Bear markets followed the great Wall Street Crash of 1929, occurred from 1937 to 1942, and following the Arab Oil Embargo crisis from 1973 to 1982. More recent examples were from 2000 to 2002 and from 2007 to 2009 in the wake of the Great Recession and Global Financial Crisis.
Secondary trends are those which are short term in nature. These generally last for several weeks to several months. Market corrections are actually a kind of secondary market trend. Such corrections are defined as a shorter term decline in market indices by from around ten percent to around twenty percent. From April 2010 through June 2010, the S&P 500 dropped from 1,200 to around 1,000. Investors at the time believed this was the end of the bull market and the start of a bear market. In fact it was only a correction as the markets turned and continued going back up afterward.
There can also be bear market rallies within the secondary market trends. These are better known as dead cat bounces. They are comprised of a price run in the markets amounting to from ten percent to twenty percent before the bigger bear market trend continues again. Such a dead cat bounce actually happened in 1929 after the initial Black Friday crash. The markets then descended into the ash can through 1932 and more or less through 1942. Another such false bounce occurred in the latter years of the 1960s and early 1970s.