A DataFrame is a fundamental data structure used in data science and analysis, particularly within the Pandas library in Python. It is a two-dimensional, size-mutable, and potentially heterogeneous tabular data structure, organized in rows and columns, similar to a spreadsheet or a SQL table. DataFrames are designed to hold various data types, such as integers, strings, and floats, making them versatile for handling real-world data. They provide an intuitive interface for data manipulation tasks, including sorting, filtering, and aggregating, and are widely utilized across various fields, from finance to scientific research, for efficient data analysis and visualization.