Which term refers to the space inside a three-dimensional object?

The term that refers to the space inside a three-dimensional object is volume. Volume measures the three-dimensional space occupied by an object, expressed in cubic units (like cubic centimeters, liters, or gallons). It quantifies how much space is contained within the boundaries of the object, making it a fundamental concept in geometry and measurement.

For example, when you fill a box with water, the volume tells you how much water it can hold, regardless of the box's shape. Understanding volume is important in various real-world contexts, such as determining how much liquid a container can hold or calculating the capacity needed for storage.

Surface area, while related, measures the total area of the object's outer surfaces rather than the space within it. Capacity often refers to the maximum amount a container can hold but is often synonymous with volume in practical usage. Mass, on the other hand, is a measure of the amount of matter in an object and does not relate to the space it occupies.