Can you translate into your own language the phrase "a semi-detached house"? If not, you may have trouble with the English word "house".

In England, more than a quarter of the population live in semi-detached houses, or "semis". Two semi-detached houses are built under a single roof, as a single building, but each has its own entrance door and pathway leading to the street outside. The building consists of two houses, that is, two separate homes.

  A pair of semi-detached houses

Contrast these with a detached house:
  A detached house

Your house can be one of a continuous row of terraced houses, a long building that may run the whole length of the street.

  A terrace of houses

But: if you live in a flat (or apartment, as house agents often describe it), in a block of flats, you do not live in a house. We repeat: if you live in a block of flats, you cannot say that you live in a house.
  A block of flats



Equally, if you work in an office block, or department store, or theatre, or hospital, you cannot describe the building as a house.

There are some apparent exceptions to these rules: we talk of the House of Windsor (meaning the dynasty of the present royal family), the House of Rothschild (meaning the mercantile firm), the House (meaning the House of Commons, or the Stock Exchange, or Christ Church, one of the colleges at Oxford University); the zodiac is divided into twelve "houses" or signs; a pub linked to one brewer is a tied house; a disorderly house is a legal euphemism for a brothel; a house style is a set of printing conventions laid down by a publisher for all his books or magazines; a church can be a house of God; a theatre which has sold all the tickets for a performance has a full house; an office block can have a name like "Bucklersbury House" over its entrance.

All the same, these should not mislead you into forgetting the primary meaning of "house" in ordinary conversation. Misuse may lead to misunderstanding or total confusion among your English listeners.