A house which doesn't attach to another house on any side is known as detached. These such houses are usually worth more than a semi detached due to the fact you have no connecting walls with neighbours, therefore less problem with noise. Detached houses are also often more individual and have more scope for extending.
Terraced houses are those joined on both sides to other property. These are usually more affordable than detached homes and semi-detached homes, and tend to all be built in the same very similar style.
Another type of house is the bungalow. These are one level houses, which were first built specifically for the elderly or those with mobility issues due to the fact that they have no stairs. In recent years however, they have increased in popularity with other buyers due to the fact they are often detached but cheaper than regular detached houses. In addition to this people tend to like the fact that they are quirky, easy to clean and are safer/more convenient for those with children.
There are also flats, which even in themselves can vary massively in size, style and cost. Flats can range from a two-storey house divided into two to multi storey, luxury apartment style flats which can cost in excessive of £1 million.