Arc lamp gas is a commonly used term to describe the gas used in the arc lamps. However, there are also other synonyms for this term that can be used depending on the context. Some of the synonyms for arc lamp gas include mercury vapor gas, xenon gas, and neon gas. Mercury vapor gas is widely used in outdoor lighting applications due to its high luminosity and long-lasting performance. Xenon gas is often used in automotive headlamps and cinema projectors due to its high color rendering ability. Neon gas, on the other hand, is commonly used in advertising signs due to its bright red glow. Overall, these synonyms can help provide a better understanding of the different applications and properties of arc lamp gas.