Fizz is the bubbly, hissing sound and feeling you get from carbonated drinks like soda or sparkling water. When you open a bottle of ginger ale, that rushing pssshhht sound is fizz escaping. The tiny bubbles that tickle your tongue and nose when you take a sip: that's fizz too.

The fizz in drinks comes from carbon dioxide gas dissolved under pressure. When you pop open the container, the pressure releases and the gas escapes as thousands of tiny bubbles. Fresh soda has lots of fizz, but if you leave it open overnight, it goes flat because the gas has escaped into the air.

The word itself sounds like what it describes: say fizz out loud and you can almost hear those bubbles popping. People use the word as a verb too: a drink can fizz in your glass, or an experiment might fizz when you mix baking soda and vinegar. Something that fizzles out starts with energy and excitement but gradually loses steam, like a bottle of soda left open too long.