A byte stream is a sequence of bytes that can be read from or written to a source, such as a file or network connection. It allows for the handling of binary data, making it suitable for various applications, including file transfers and multimedia processing. Byte streams are essential in programming languages like Java and Python, where they facilitate input and output operations. In a byte stream, data is processed one byte at a time, which is efficient for handling large amounts of data. This contrasts with character streams, which deal with text data. Byte streams are commonly used in scenarios where precise control over data representation is required, such as in image or audio file manipulation.