We’ve been asked this question by many of our clients, so we figured we ought to publish our definition for you to reference. Why? Because we’re nice like that, and also because we believe many of the explanations out there over complicate things and talk in a language that most people just don’t speak or understand.
No pressure on us then.
An open source application is simply any computer program that allows you to tinker under its hood.
Standard applications that you can purchase for your computer (such as Microsoft Office) will normally not allow you access to the code that makes the application work. Programming code is basically a set of instructions that tells the computer what to do. If the code is inaccessible you are therefore restricted by whatever features and tools have been supplied with the application.
Open source applications work in the opposite way. They provide access to all of the programming code so that you can change the application to work the way you want it to. This means if there is a feature you don’t like, or think is missing, you can access the code and make the relevant changes, creating a better and tailored application to fit your unique needs.