A slicer is a tool used in data visualization software, such as Microsoft Power BI or Tableau, that allows users to filter data interactively. By selecting specific criteria, users can narrow down the information displayed in charts and tables, making it easier to analyze trends and patterns. Slicers enhance user experience by providing a simple way to manipulate data without needing complex queries. Slicers can be applied to various data types, including dates, categories, and numerical values. They often appear as buttons, dropdowns, or sliders, enabling users to quickly adjust their view. This functionality is particularly useful in dashboards, where real-time data insights are essential for decision-making.