A skyscraper is a multi-story building whose architectural height is at least 100 meters. If the height is unknown, a building can be assumed to be a skyscraper if it has at least 40 floors.

In many contexts (apart from SKYDB Definitions) this term is applied to a wider range of tall buildings, using criteria such as relative height or framing system. Its original use in the 19th century was applied to office buildings in New York City which towered above their surroundings. Historians also refer to early steel cage building frames as skyscraper construction.

The 40-floor rule provides an assumption only when the height is unknown. Supertall buildings meet the higher architectural-height threshold of 300 meters.