Rooftop

Origin

roof + top

Full definition of rooftop

Adjective

Atop a roof; on a roofIn recent years, we've seen Bangkok become the unofficial rooftop bar capital of the world.
—Thailand's Islands and Beaches, Lonely Planet

Noun

rooftop

(plural rooftops)

(somewhat formal) The area atop a roofWhy do you think the rooftop of their apartment building is called "tar beach"? (Answers may vary.)
—Multicultural Books for Primary Grades, Liz Rothlein
the top layer of a roof, the material covering or composing a roofThe house itself was a mound of red baked bricks and a tin rooftop.
—The Chocolate Shop Perverts, Ernest Alanki

Usage notes

As it refers specifically to the area atop the roof or to the top area of the roof, "rooftop" is not always synonymous with the entire "roof". For instance, "the rooftop blew off the house" would (probably unintentionally) imply some lower level of the roof remained. Compare similar location words such as desktop.