What is a three-letter word that starts with gas?

One three-letter word that starts with "gas" is "gas." "Gas" is a common term used to describe a state of matter. It refers to a substance that is in its gaseous state, characterized by molecules or atoms that are widely spaced apart and have high kinetic energy. Gases are shapeless and expand to fill the container they occupy. Examples of common gases include oxygen, nitrogen, hydrogen, carbon dioxide, and helium.