A tool palette is a graphical user interface (GUI) element used to group together special functions in an application, usually of the kind used to create and edit media such as photo and video editing software, sketch and painting applications, 3-D modeling and animation and CAD applications. The tool palette groups together shortcuts to functions, usually in the form of icons or widgets. It is akin to the artist's palette used to hold and mix the different paint colors needed to create a painting.
A tool palette is also known simply as a palette.
A tool palette is a suite of tools and functions available to the user via GUI elements like icons and widgets found within creation software such as Photoshop and AutoCAD. The tools are often arranged and grouped according to specific function and the user can have multiple tool palettes open and even create their own custom grouping, but this entirely depends on the application if this feature is supported.
A tool palette often includes creation tools such as those that create lines and shapes or selection tools and edit tools. Of course, the type of tools available in the palette depends on the application and can differ even between versions of the same software. A tool palette can appear as a section within the app GUI, usually to the sides, as a tool bar, or even as a movable floating sub-window.