A-Cover (Top Lid): The outer back cover of the screen. This is the side that shows the brand logo when the laptop is shut.
B-Cover (Screen Bezel): The inner plastic frame or border that surrounds the LCD display panel and holds the webcam.
C-Cover (Palm Rest / Keyboard Deck): The upper surface around the keyboard where your hands rest while typing, which usually includes the touchpad.
D-Cover (Bottom Base): The bottom underside piece that touches the desk, featuring ventilation slots and rubber feet