The term 'io routine' is a well-known term in the field of computer programming. It refers to a subroutine or a set of commands that relate to input and output (I/O) operations between a program and a peripheral device such as a disk drive, printer, or keyboard. Some synonyms for 'io routine' include 'I/O function,' 'I/O handler,' 'device driver,' 'input/output control program,' and 'I/O module.' These synonyms are interchangeable and typically refer to the same concept in programming. The use of 'io routine' or its synonyms is essential for developers to seamlessly communicate with hardware components and ensure successful data transfer and manipulation.