When you hunker down, you settle into a safe, sheltered position. Some people evacuate their homes during a big hurricane, while others hunker down and wait for the storm to pass.
This term is such a popular way to describe taking shelter from a storm that it's become a weather report cliché. You might hunker down in your basement during a tornado watch, but you can also hunker down during an argument, refusing to budge from your stated position. Hunker comes from Scottish — it means "crouch on your heels" or "squat." Sometimes the phrase is also used to mean "get to work," like when you hunker down and finish your homework.