“OHLC” stands for “Open, High, Low, Close”, and this is a chart designed to help illustrate the movement of a stock’s price over time (typically a trading day, hour, or minute)
OHLC charts are also known as “Bar Charts” because they display the information as a series of line segments instead of as a continuous line. Bar charts are very useful to see how prices are moving in a period of time – the longer the line segment, the more the price has moved during that time.
The example above is a bar chart for Google, with the bars representing 5 minute intervals. The top of each line is the “high” price reached in that period of time, while the bottom of each line is the “Low” point. The longer the lines, the more volatile the stock.
You can find these charts on our Quotes page for every US stock, and most international stocks.