Great question!
In layman's terms: SVG file is a vector file that will tell your cutting machine, such as a Cricut, where to cut lines and you can scale it (make it larger or smaller) without ruining its structure!
And, in technical terms: The SVG file stands for "Scalable Vector Graphics." SVG is a vector graphic format that's based on XML (Extensible Markup Language) and is used to display a variety of graphics on the Web and other environments. For SVG, there are combinations of different shapes, paths, and text elements allowing you to create all kinds of visuals.
Great for crafting!!