DriverSide's Car Dictionary has the most comprehensive definitions of automotive terms. This auto glossary can help you decipher what your mechanic is fixing and what the purpose or function of the particular auto part or accessory is for. We have taken the mystery out of automotive service jargon, so that you don't have to.
This is what is sounds like it'd be--the mix of gasoline and air that allows your engine to produced power. There is an ideal ratio of air to fuel that is most conducive to a complete burn of the gasoline, which is 14.6 parts air to 1 part air, also known as the "stoichiometric ratio." (I challenge you to work that into a sentence sometime int he next 6 days without the person you're talking to noticing.)