Great question! All three words are often used interchangeably, but there is a technical difference.

Software- the programs and other operating information used by a computer. Software can be made up of more than one program. All-encompassing term that is often used in contrast to hardware (the tangible parts of a computer)

Application- A program or group of programs that is designed for the end user. Application software (an application) is a set of computer programs designed to permit the user to perform a group of coordinated functions, tasks, or activities. Application software cannot run on itself but is dependent on system software to execute.

Program- A set of instructions telling a computer what to do.

"All applications are programs, but a program is not necessarily an application. For example, there are always lots of programs running on the background of an operating system, but since they weren't developed for the end-user, they are not applications. On the other hand, Windows Media Player and Firefox, for example, are applications. They have a Graphical User Interface." - https://www.quora.com/What-is-the-difference-between-an-app-and-a-program

Hope this helps. :)

Exceptional, clear, comprehensive answer, Kristopher Van Sant. Thank you!

Cool Answer! Helped me a lot! Thanks Kristopher!

Great question and answer! Thanks!