Material Design is a design language developed by Google that simplifies Android application design through use of grid-based layouts, responsive animations, padding, and depth effects like lighting and shadows. It addresses issues with device variety, branding, usability, and development/design efforts. Key aspects of Material Design include surfaces, bold graphic design using typography, grids, color palettes, and imagery, animation transitions, and UI widgets like RecyclerView, CardView, floating action buttons, and CoordinatorLayout.