Software is a set of instructions that must be followed and executed by a mechanism, be it a computer or an electromechanical device. It is the generic term used to describe programs, applications, scripts, macros and instructions for directly embedded code (firmware), in order to dictate what a machine should do.
Every program on your computer, mobile phone, tablet, smart TV, video game console, set-top box and etc. is software, be it a text editor, a browser, an audio or video editor, a game, an app streaming and so on. Software can come in many forms, from an application on a cell phone to a set of perforated cards, used on electromechanical computers.