[18] Whether or not that is so, it is, I think, plain that the definition in question was adopted in order to include not only a single dwelling that is detached but also a duplex. Presumably another intention in, or effect of, adopting that definition is to exclude what counsel in argument described as a "triplex", or a row of terrace houses such as one sometimes sees in Brisbane and more commonly in Sydney. The word "duplex" is, I suspect, a comparatively recent importation from the United States, an impression which receives some support from the entry for the word in the Macquarie dictionary. According to Webster's, it is used in America to denote a house with two apartments, which is the sense in which it is used in the definition in Schedule 2. In England, and in the South Africa of my youth, such houses were commonly referred to as "semi-detached" as combining two residences or dwellings under one roof which were divided in the middle by a vertical party wall. The Schedule 2 definition was evidently designed to label such buildings as "detached" for the purposes of ss 7 and 8 of the Act, even though they might sometimes be spoken of as semi-detached.