Hollow means empty inside, with nothing filling the space within. A hollow tree trunk might look solid from the outside, but when you peek inside, you find an empty cavity where the wood has rotted away. A hollow chocolate bunny feels light when you pick it up because it's just a thin shell with air inside, unlike a solid chocolate bar.

When you knock on something hollow, it makes a distinctive echoing sound, different from the dull thud of something solid. That's why people tap on walls to find hollow spaces behind them, or why a hollow log sounds different when you hit it than a solid one does.

The word can also describe feelings or experiences that seem empty or meaningless. A hollow victory is one that should feel good but doesn't, like winning a game only because your opponent got injured. A hollow promise sounds nice but lacks real commitment behind it. When someone's laugh sounds hollow, you sense they're not genuinely amused.

You might feel a hollow sensation in your stomach when you're nervous or disappointed, that empty, unsettled feeling that something important is missing. In this way, hollow captures both physical emptiness and emotional emptiness: the absence of something that should be there.

As a noun, a hollow is a hollow place, like a small dip or sheltered spot in the ground, or a hollowed-out space inside something.