Mash means to crush something into a soft, lumpy mixture, usually by pressing down repeatedly with force. When you make mashed potatoes, you boil potatoes until they're soft, then mash them with a tool called a masher, turning solid chunks into a creamy heap. You might mash bananas for banana bread, mash avocados for guacamole, or mash berries to make jam.

The word captures that specific action of pressing and crushing: not chopping (which cuts), not stirring (which mixes), but smashing something down until it breaks apart and becomes mushy.

In cooking, foods are often mashed to change their texture and make them easier to eat or combine with other ingredients. Baby food is frequently mashed so babies can eat it without teeth. Some people like their mashed potatoes smooth and creamy, while others prefer them chunky, with lumps still visible.

The word can also describe forcefully pressing buttons, like when someone frantically mashes the elevator button, hoping it will arrive faster, even though pressing it multiple times doesn't actually help. In video games, players sometimes button mash, rapidly hitting all the controls at once when they're panicking or don't know the right combination of moves.