Build means to create something by putting parts or materials together according to a plan or design. When you build a treehouse, you're connecting pieces of wood into a structure where none existed before. When engineers build a bridge, they're assembling steel, concrete, and cables according to a careful plan.

Building means constructing something with purpose and design, whether you're building a snow fort, building furniture from a kit, or building a robot for a science competition. The process usually involves planning what you want to make, gathering the right materials, and putting them together in the right order so everything fits and works properly.

The word also describes creating things that aren't physical. You can build a friendship by spending time together and being reliable. A lawyer builds a case by gathering evidence. A story builds tension as it moves toward an exciting climax. Someone might build their confidence through practice, or build good habits through repetition.

When we talk about someone's build, we mean their physical structure: a gymnast might have a lean build, while a weightlifter might have a muscular build.

The past tense is irregular: built. Once something is built, we say it has been constructed. A building is a structure like a school or library.