What makes up the markets? When you hear someone say that the markets are up today, they are saying that on average the stocks that make up that index (market) did good. It doesn't mean that all the stock with in that market were up, just on the average of those stocks were.
The main three markets that are refer to often are the DOW (DJIA - Dow Jones Industrial Average), NASDAQ (National Association of Securities Dealers Automated Quotations) and the S&P 500 (Standard and Poors). There are a few others, but I'll just mention these three.
Within the DOW there are sectors that cover different ares of the economy, financial, commodities, retail, agricultural, energy, and more than I care to list in this article. The NASDAQ is mainly made up of technology and biotech type companies. To list a few, there's Google, Apple, Sirius/XM and Akeena Solar.
The Standard and Poors 500 (S&P 500) is made up of five hundred different stocks. Each is selected for liquidity, size, and industry. The index is weighted for market capitalization. The S&P 500 is the benchmark of the overall market.
Other things that should be considered when you think of the markets is the dollar. The dollar plays a big part of what goes on in the markets. if the dollar is weakening then American stocks typically lose value and the reverse happens when the dollar gains strength. It will also play a part in the world economy which in turns effects our economy as well.
These are just a few of the basics things to know when you want to trade stocks to make money