A hummock is a small, rounded hill or mound that rises above the surrounding ground. Picture walking through a meadow and noticing gentle bumps in the earth, each one just high enough to sit on or scramble over. These little rises are hummocks.

You'll find hummocks in many landscapes. In marshes and wetlands, hummocks form when plants grow in clumps, creating dry spots that rise above the water. Arctic explorers encounter hummocks of ice: frozen mounds pushed up when sheets of sea ice collide and pile up. On golf courses or in forests, hummocks might be grassy knolls or mounds of earth.

Hummocks are bigger than bumps but smaller than hills. They're the kind of feature you might not notice on a map, but walking across a field full of them would make your path rise and dip every few steps. Kids playing capture the flag might hide behind a hummock, or rest on one while catching their breath.