tailpipe
The pipe through which exhaust gases are expelled from an internal combustion engine.
Noun
pl: tailpipes
A tailpipe refers specifically to the final section of the exhaust system that vents gases into the atmosphere. While people often use "exhaust" as a general term for the entire system (including the manifold, catalytic converter, and muffler), "tailpipe" describes the actual visible pipe at the rear of the vehicle.
In casual conversation, it is used to describe the physical location or the visible output of a car. In technical or mechanical contexts, it is used to identify the specific part being repaired or modified, such as when discussing "dual tailpipes" for performance or aesthetic reasons.