To upgrade means to replace something with a better, newer, or more advanced version. When your family upgrades their car, they trade in the old one for a model with features they didn't have before. When you upgrade your bicycle, you might get one with more gears or better brakes. Airlines sometimes upgrade passengers from regular seats to first class seats with more space and comfort.

The word carries a sense of moving upward to something superior. A restaurant might upgrade its menu by adding higher-quality ingredients. A phone company releases software upgrades to fix problems and add new capabilities. In video games, you upgrade your character's armor or weapons to handle tougher challenges.

An upgrade (as a noun) is the improved version itself: “The latest upgrade to the app made it much faster.”

People also use upgrade more playfully. Someone might joke that switching from a packed lunch to a pizza party is a serious upgrade. But the core meaning stays the same: exchanging something for a better alternative. The opposite is a downgrade, when you move to something worse or less capable.