Conditional Format Gradient Color is a feature in spreadsheet applications that allows users to apply a gradient color to a cell or range of cells based on specific conditions. It is used for visual data representation and can make data more easily understandable. In Microsoft Excel, for instance, this feature can be accessed under the 'Conditional Formatting' menu. The gradient can be set to change from one color to another based on cell values, such as from low to high or vice versa.