Trailer is a load carrying vehicle used for a vehicle or machine. It is thought that the trailer is primarily designed and used to carry loads of very large weights. Trailer has a certain load carrying capacity and is generally used to carry very large and heavy loads.
Trailer, on the other hand, is a load carrying vehicle mounted on the back of vehicles. Trailer is pulled by vehicles and is often used to transport smaller loads. The load carrying capacity of the trailer may be lower than the trailer and is often used to transport lighter loads such as household goods, ATVs, bicycles.
In summary, the trailer is designed and used to carry larger and heavier loads, while the trailer is designed and used to carry smaller loads.