How To: Display descriptions from layer symbology in the ArcMap legend
Descriptions are optional additional text to display in a legend next to or in place of class labels.
Descriptions are especially useful to display labels and other information with different text formatting options. For example, to show the common name of a species with regular text, and the scientific name with italics.
Note: Legend descriptions are only applied when items are symbolized as a single symbol rather than in groups or categories.
The instructions provided describe how to display descriptions from layer symbology in the ArcMap legend.
In ArcMap, double-click the legend to open the Legend Properties dialog box.
Select the Items tab.
In the item list box, right-click the appropriate item and select Properties.
In the Legend Item Properties dialog box, select the General tab.
Check the Show Descriptions check box.
Note: This box is inactive if no description exists.
Optionally, click Description Symbol to modify text symbol properties for the description.
Here is an example of a legend showing a label and a description.