There are various synonyms for the term "automobile exhaust." One term that is commonly used is "vehicle emissions," which refers to the gases that are released into the air by a car or other motor vehicle. Another term is "exhaust fumes," which describes the toxic gases that come out of a car's exhaust pipe. "Tailpipe emissions" is yet another synonym, which specifically refers to the emissions that come out of the back of a car's exhaust pipe. Other, more technical synonyms for automobile exhaust might include terms such as "combustion byproducts" or "internal combustion emissions." Ultimately, all of these terms refer to the same thing: the harmful gases that cars and other vehicles release into the air.