The phrase "deck lid" refers to the trunk of a car. It is the hinged cover that covers the area where you put your luggage or belongings. Full definition
It has a complex mechanism that stacks three aluminum sections very neatly beneath the rear deck lid in 30 seconds. (automotive.com)
Also comes with a small deck lid spoiler, rims, leather steering wheel and sportier seats. (edmunds.com)
Rear styling features are functional, including the rear - bumper bottom spoiler and deck lid with an expanded trunk edge, both of which make the car more slippery than its predecessor. (wardsauto.com)