Final answer:
A gazebo is a small, often ornamental building in a garden that is typically open on all sides and may have a roof. It is used for relaxation, socializing, or enjoying the view of the garden.
Step-by-step explanation:
A small, often ornamental building in a garden is known as a gazebo. Gazebos are typically freestanding structures with a roof, open on all sides to provide a shady retreat from which one can enjoy the garden. They can be quite decorative, adding both function and beauty to the outdoor space. Unlike greenhouses, which are enclosed to create a controlled environment for plants, or pergolas and arbors, which are more open frameworks often used to support climbing plants, gazebos are primarily meant as seating areas.