Equivolume
A chart that compares price and volume and plots them together as one piece of data. The height of each bar represents the high and low for each period, and the width represents the volume relative to the total shares traded over the time period being viewed.
Investopedia Commentary
This type of chart is very similar to Japanese candlesticks except that volume is incorporated into the data point rather than added as an indicator on the side. Generally, a wide bar is deemed to be more significant than a thin bar because large volume usually precedes a significant price move.
Related Links
The Art of Candlestick Charting - Part 1
The Art of Candlestick Charting - Part 2
The Art of Candlestick Charting - Part 3
The Art of Candlestick Charting - Part 4
Introduction To Technical Analysis
See also: Candlestick, Indicator, Volume