Hot rods are typically American cars with large engines modified for linear speed. The origin of the term "hot rod" is unclear. One explanation is that the term is a contraction of "hot roadster," meaning a roadster that was modified for speed. Another possible origin includes modifications to or replacement of the camshaft(s), sometimes known as a "stick" or "rod". A camshaft designed to produce more power is sometimes call a "hot stick" or, here, a "hot rod". Roadsters were the cars of choice because they were light.