With the exception of drawers and a toekick, an upper and lower cabinet share the same basic elements.
Carcass. Cabinet box; supports weight of countertop and items on its shelves.
Corner Braces. Keep carcass square during transport and installation.
Door. Four types: flat panel (shown), raised panel, slab, and glass front.
Drawer. Moves on metal glides fitted to the sides or bottom.
Face Frame. Stiles and rails that stiffen the carcass and provide a mount for hinges. (Not present with full overlay doors.)
Hinge. Can be visible or hidden, depending on door type.
Toekick. Closes gap at cabinet base and provides a recess for feet.