L-head is often used to describe a certain type of engine design, specifically an internal combustion engine with the intake and exhaust valves located on one side of the cylinder. However, there are several other synonyms that could be used to describe this type of engine design. Some other common terms include side-valve, flathead, and T-head. Regardless of the preferred term, these engines were popular during the early 20th century due to their simplicity and reliability. While they may not be as common today, they remain an important part of automotive history and engineering.