The Free Software Movement is a philosophy and movement that advocates for the freedom to use, study, distribute, and modify software. There are several terms that are used interchangeably with the Free Software Movement, including open source software, libre software, and free and open source software (FOSS). While each term emphasizes a slightly different aspect of the movement, they share the same core values of promoting freedom and collaboration in software development. Open source software highlights the collaborative and community-driven nature of the movement, while libre software emphasizes the freedom to use and modify software. FOSS combines these concepts to represent the complete suite of values represented by the Free Software Movement.