|building = semi|
|A semi-detached house.|
|Used on these elements|
|Status: in use|
|Tools for this tag|
In Britain semis usually have 2 floors, but semi-detached bungalows are common in some areas. It is not clear whether the semi tag or building=bungalow should be preferred in this case: indeed, perhaps building=bungalow_semi may be a suitable alternative.
There are a number of synonyms for this tag (see listing below). The only one with widespread usage is building=semidetached_house which has more than twice the number of tagged elements compared with building=semi, and is spread a bit more over the world. See the taginfo map:
building=semi has been in use longer (see below), and probably accords better with standard usage in Britain, but it may be non-obvious to mappers from outside English-speaking areas where the term is commonly used.