A line chart is a method of depicting price action of an asset by joining corresponding points of key data using straight line segments. A line chart is mostly used to show the trend of the asset over time. So the chart window is looked at as having a y-axis and x-axis, in which price forms the y-axis variable and time forms the x-axis variable.
Chart showing the various points plotted for price action, and how these points are joined using line segments to form a line chart).
In demonstrating the price action of an asset over a specific time frame, specific points are plotted on the chart corresponding to the length of time being measured, and line segments are used to join these points. For instance, in the chart shown above, the time frame is one hour. So specific points corresponding to one-hour gaps are plotted on the x-axis of the chart, and then lines are used to connect these dots together to form the line chart. If you can visualize line charts from elementary Mathematics, then you can appreciate line charts.