Computer instructions or data. Anything that can be stored electronically is software. The storage devices and display devices are hardware.
The terms software and hardware are used as both nouns and adjectives. For example, you can say: "The problem lies in the software," meaning that there is a problem with the program or data, not with the computer itself. You can also say: "It's a software problem."
The distinction between software and hardware is sometimes confusing because they are so integrally linked. Clearly, when you purchase a program, you are buying software. But to buy the software, you need to buy the disk (hardware) on which the software is recorded.
Software is often divided into two categories:
Systems software : Includes the operating system and all the utilities that enable the computer to function.
Applications software : Includes programs that do real work for users. For example, word processors, spreadsheets, and database management systems fall under the category of applications software