The documentation on each display item in Visual Studio\'s Environment options for Fonts and Colors is lacking. There is a documentation page on msdn,
There is no documentation available for Highlighted Definition, Highlighted Reference, and Highlighted Written Reference. These all pertain to highlighting similar items within source code to the item currently selected.
Highlighted Definition: Specifies the highlight color for where the currently selected item is defined (e.g., member definition, type definition, constructor, ...).
Highlighted Reference: Specifies the highlight color for where the currently selected item is referenced.
Highlighted Written Reference: Specifies the highlight color for where the currently selected item is assigned a new value.
In the example below: