Configurable options are configurable via the preferences dialogue, which can be invoked from the preferences menu item, found under "Settings" in the gnome-terminal menubar.
Whilst most options are self-explanatory, some are discussed below in more detail.
Sets the terminal class for the current configuration or terminal. Refer to the section on classes for further information.
Defines a list of characters (or character classes) that should be considered 'word characters'. These are used when selecting text by word.
Gnome terminal fully supports the colour extensions used by xterm. These options allow you to control those colours.
gnome-terminal supports four colour schemes: the Linux console scheme, the colour Xterm scheme, the rxvt colour scheme, and a completely customisable colour scheme. These define the intensity and colours for the sixteen ANSI colour combinations that are supported by these terminals.
If you have selected the custom option, then all 16 colours (nominally 8 colours, and 8 bright colours) can be customised by clicking on the colour selectors.
When no colours have been requested by the application running inside of gnome-terminal, gnome-terminal allows you to over-ride the default terminal foreground and background colours.
The following options are available: white on black, black on white, green on black, black on light yellow, and custom. How these actually appear depends on the palette selected (for the white on black and black on white options). Custom allows you to select the default foreground and background colours individually and separate to the palette.
Additionally, the user can drag a colour from the rectangular box beneath the colour wheel from any GNOME colour selector or colour source and drop it into the terminal. If the user drops the colour on a blank space, it will set the background, if the user drops the colour on a cell that contains a character, it will change the foreground. This will also automatically change to custom colours, and set the custom foreground or background colour.