In common usage and classical mechanics, a physical object or physical body is a collection of matter within a defined contiguous boundary in three-dimensional space. The boundary surface must be defined and identified by the properties of the material, although it may change over time. The boundary is usually the visible or tangible surface of the object. The matter in the object is constrained to move as one object. The boundary may move in space relative to other objects that it is not attached to. An object's boundary may also deform and change over time in other ways.

भौतिकी में, भौतिक पिण्ड या भौतिक वस्तु पदार्थ के अभिज्ञेय संग्रह है, जो त्रिविम अवकाश में कुछ सीमा-शर्तों का पालन करते हुए स्थानान्तरण या घूर्णन गति करता है।