What term describes objects or coordinate systems used for taking measurements?

The term "frames of reference" is used to describe the objects or coordinate systems that are established for taking measurements in physics. A frame of reference provides a perspective from which measurements are made and can include a coordinate system that defines how space and time are observed. It is crucial for understanding motion and describing the position of objects, allowing various observers to record and interpret events consistently.

For instance, when analyzing the motion of a car, one may choose a stationary frame of reference (like the ground) or a moving frame of reference (like another car). This choice affects how the motion is perceived and measured, highlighting the fundamental importance of frames of reference in experimental and theoretical physics.

While the other options might relate to measurements in different ways, they do not capture the full scope of the concept as effectively as frames of reference. Reference points are locations used to define an object's position but do not encompass the broader context of measurement systems. Measurement systems refer more to the tools and methods used, and coordinate grids are specific types of frames within mathematics rather than capturing the wider application in physics.