A heatmap is a data visualization tool that uses color to represent the intensity of data values across a two-dimensional space. It helps to quickly identify patterns, trends, and areas of interest within a dataset. Commonly used in fields like data analysis, marketing, and healthcare, heatmaps can display information such as website user activity or geographical data. In a heatmap, warmer colors like red and orange indicate higher values, while cooler colors like blue and green represent lower values. This visual representation makes it easier for users to interpret complex data at a glance, facilitating better decision-making and insights.