To fortify means to make something stronger or more secure against attack or damage. When a medieval castle was fortified, workers might add thicker walls, dig deeper moats, or build extra towers. Today, a country might fortify its borders by adding security measures, or a homeowner might fortify their house against storms by installing stronger shutters and reinforcing the roof.

The word originally comes from military contexts: making a place harder to conquer. Soldiers would fortify their position by building protective barriers and stockpiling supplies. But fortify works beyond warfare too. When you fortify yourself with a good breakfast before a long hike, you're building up your strength and energy. Many cereals and breads are fortified with extra vitamins and minerals, meaning those nutrients have been added to make the food more nutritious.

You can also fortify your courage before doing something scary, or fortify an argument by adding stronger evidence. A lawyer might fortify her case by finding another witness. The core idea stays the same: taking something and making it stronger, more resilient, and better able to withstand whatever challenges lie ahead.