A file pointer is a variable that indicates the current position in a file when reading or writing data. It helps programs keep track of where they are in the file, allowing them to access specific parts of the file efficiently. When a file is opened, the file pointer is typically set to the beginning, and it moves as data is read or written. In programming, file pointers are commonly used in languages like C and Python. They enable developers to perform operations such as seeking to a specific location, reading data, or appending new information without having to load the entire file into memory.