A pivot table is a data processing tool commonly used in spreadsheet applications like Microsoft Excel and Google Sheets. It allows users to summarize, analyze, and present large sets of data in a more manageable format. By rearranging rows and columns, users can easily view different perspectives of the data, making it simpler to identify trends and patterns. Pivot tables can aggregate data through functions such as sum, average, or count, providing quick insights without altering the original dataset. They are particularly useful for tasks like financial analysis, sales reporting, and any situation where data needs to be organized for better understanding.