A DataFrame is a two-dimensional, size-mutable, and potentially heterogeneous tabular data structure commonly used in data analysis. It is part of the pandas library in Python and allows users to store data in rows and columns, similar to a spreadsheet or SQL table. Each column can hold different data types, such as integers, floats, or strings. DataFrames provide various functionalities for data manipulation, including filtering, grouping, and merging datasets. They also support operations like statistical analysis and data visualization, making them a powerful tool for data scientists and analysts working with large datasets.