If you mean a Mac (iMac, MacBook, etc.), you can "trash" the Firefox App to uninstall it. See this article for steps: [[Uninstall Firefox from your computer]] (If it shows you info for Windows, use the selector in the right column to switch it to Mac.) If you mean iOS (iPad, iPhone), I can't recall for sure, but I think long-pressing the program icon on the home screen will make it possible to trash the app.