I have to admit, when I ran across this collection of 16 of the Best WordPress Material Design Themes for Flat, Cool Websites I really didn’t know what to make of it. I mean, what’s a flat theme vs a material design theme? They’re pretty similar, but I had trouble differentiating between the two. Well, it turns out, it’s a matter of degrees. Flat themes offer you absolutely no ‘dimensionality’ to the design, whereas material design themes may have a few pixels worth of drop shadow under images. It’s sort of like the image is three dimendional, just barely rising off the surface of the page, as if it’s resting on a small, flat box underneath.
Here’s a great example of what material design looks like from Driven Local.
So, yeah, that’s basically what a material design…design looks like, note the subtle use of shadows. The color scheme tends to be bold too, but I’ve noticed that that’s not quite as consistent as the fact that it’s got just that hint of three dimendionality. Anyway, material design and flat design are certainly cousins and either could look great for your website.