While the term “free software” seems self-explanatory, there’s a lot of confusion surrounding the actual definition and usage of “free.” Before we define it, it’s important to know that free software is usually used interchangeably with open source software. Free software is exactly what it says on the tin; you can download it and run it without having to pay the owner a dime. Although the software is free to use, it may contain restrictions that make it difficult to modify, distribute, or resell. Open source software eliminates these restrictions by not only allowing the user the download the software, but also to study and change the source code and redistribute the modified program. The Latin words “gratis” and “libre” are often used in place of “free” and “open source” to prevent ambiguity.