A
tower block,
high-rise,
apartment tower,
residential tower,
apartment block,
block of flats, or
office tower is a tall building, as opposed to a low-rise building and is defined differently in terms of height depending on the jurisdiction. It is used as a residential, office building, or other functions including hotel, retail, or with multiple purposes combined. Residential high-rise buildings are also known in some varieties of English, such as British English, as
tower blocks and may be referred to as
MDUs, standing for
multi-dwelling units. A very tall high-rise building is referred to as a skyscraper.