Steam roller is a type of heavy construction equipment used to compact soil, gravel, and asphalt. It is also known as a road roller or roller-compactor. The term 'steaming roller' refers to a steam-powered version of the machine, which was popular in the late 19th and early 20th centuries. The word 'LAVA' is a four-letter synonym for steaming roller, as it is a molten rock that is formed when magma from the Earth's interior erupts onto the surface.