At the early stages of concept acquisition, physical properties are inseparable of the concepts they form. With development, the concept seems to depart from the physical entities from which it emerged and seems to exist beyond its physical attributes. Numerosity is an abstract concept; however, physical properties such as diameter, area, and density have been shown to affect its perception in nonsymbolic comparison tasks. It remains unclear how these properties interact with numerosity and which property is most influential. We equated the ratio of 3 physical properties (average diameter, total surface area, and convex hull area) to the numerical ratio in order to examine which property is most discriminable and, therefore, most likely to be used. Our results demonstrate that convex hull is the most discriminable property. We suggest that holistic processing through global properties, such as convex hull, bridges between the physical world and abstract concepts.