Articulation in architecture means how different parts of a building are connected together. Think about how you might connect toy building blocks together to make a castle. You might stack the blocks on top of each other or put them side by side, but you might also want to connect them in different ways by using special pieces that help them fit together.
In architecture the same thing happens, but instead of toy blocks, architects use materials like bricks, stone, or wood. They connect these materials together in different ways to create different patterns and styles of buildings. For example, if you look at a building with columns (tall, thin pillars) you can see how the columns connect with the rest of the building. This is one way that architects use articulation.
Another way that architects use articulation is by adding decorative details to the building. Just like when you draw a picture and color it in, architects might add different textures or patterns to different parts of the building. This helps the building look more interesting and unique.
In general, articulation in architecture is all about how the different parts of a building fit together to create a cohesive, functional, and beautiful structure.