There are only two basic definitions for bullish and bearish volume:
2. Bearish volume is increasing volume on down-moves and decreasing volume on up-moves.
Knowing this is only a start and in many cases, not a great deal of help for trading. You need to know more than this general observation. You need to look at the price spread and price action in relation to the volume. Most technical analysis tools tend to look at an area of a chart rather than a trading point. That is, averaging techniques are used to smooth what is seen as noisy data. The net effect of smoothing is to diminish the importance of variation in the data flow and to hide the true relationship between volume and the price action, rather than highlighting it!
The market is an on-going story, unfolding bar by bar. The art of reading the market is to take an overall view, not to concentrate on individual bars. For example, once a market has finished distributing, the ‘smart money’ will want to trap you into thinking that the market is going up. So, near the end of a distribution phase you may, but not always, see either an up-thrust (see later) or low volume up-bars. Both of these observations mean little on their own. However, because there is weakness in the background, these signs now become very significant signs of weakness, and the perfect place to take a short position. Any current action that is taking place cannot alter the strength or weakness that is embedded (and latent) in the background. It is vital to remember that near background indications are just as important as the most recent.
As an example, you do exactly the same thing in your life. Your daily decisions are based on your background information and only partly on what is happening today. If you won the lottery last week, yes, you might be buying a yacht today, but your decision to buy a yacht today will be based on your recent background history of financial strength appearing in your life last week. The stock market is the same. Today’s action is heavily influenced by recent background strength or weakness, rather than what is actually happening today (this is why ‘news’ does not have a long-term effect). If the market is being artificially marked up, this will be due to weakness in the background. If prices are being artificially marked down, it will be due to strength in the background.