These are known as the Tenement Management Scheme (TMS).
"Tenement" is defined in section 26 of the Tenements (Scotland) Act 2004 as:
a building or a part of a building which comprises two related flats which, or more than two such flats at least two of which—
(a) are, or are designed to be, in separate ownership; and
(b) are divided from each other horizon...