A property consists of an integer and a string, and is stored in the symbol file. There are a number of properties that are recognized by Xic. Every database object, including cells, instances, and geometrical objects, has the native ability to accept properties, though this is enabled selectively. The Edit Menu contains the main commands for applying properties: the Properties command which brings up the Property Editor for manipulation properties of objects, and the Cell Properties command which brings up a similar editor for manipulating properties of the current cell.
In schematic layouts, properties define electrical parameters for devices, and are used when generating SPICE output. In physical layout mode, almost any number/string pair can be added, though Xic reserves some numbers for internal use, such as to store the grid used for the layout, or the GDSII end style for wires. In addition, there are reserved ``pseudo-property'' numbers that are not saved as properties, but rather set or return information about the object.