A moduli space is a mathematical concept that classifies objects based on their properties, allowing for the study of families of similar objects. For example, in algebraic geometry, it can represent different shapes of curves or surfaces, where each point in the space corresponds to a specific object with certain characteristics. In physics, particularly in string theory, moduli spaces help describe the different possible shapes of extra dimensions. These spaces are crucial for understanding how various physical theories relate to one another and how they can be visualized in a structured way, often involving complex geometric structures like Calabi-Yau manifolds.