Refers to a software application that runs only on a particular type of computer. Programs that run on a variety of different types of computers are called machine independent.
Almost all programs have some machine dependencies (that is, they run somewhat differently on different types of computers), but the degree of independence can vary widely. Machine-independent programs give you more flexibility: if you buy a new type of computer, you can continue using the same software package instead of learning a new one. On the other hand, machine-dependent programs often take advantage of special hardware features of a particular computer, making the programs faster.
Another term for machine dependent is device dependent, but whereas machine dependent usually refers to the computer, device dependent can refer to a dependency on any device, like a printer.