A trailer is sometimes called a mobile home. They are the same thing, a cheep house on wheels. Once you wear out your welcome, you move it to the next town. While a modular home is very different from a mobile home or trailer. Modular homes today have 2x6 walls and provide similar quality to a stick by stick built home. In the english language, there is no such thing as a "traylor". However, it could be a West Virginia thing?