The horizontal bar at the top of the Photoshop and ImageReady interface windows that contains all available options for the currently selected tool.
One of many control elements you can use to fine-tune your use of Photoshop and ImageReady tools. A palette is associated with a single element of the image (for example, the Brushes palette controls the size and shape of the cursor when you are using a painting tool). Each palette has a drop-down menu of options associated with the element it controls.