understanding time: Is time simply the rate change?

Since for some reason this question has resurfaced, I would like to point to a similar one posed later than this.

Observation of change is important to defining a concept of time. If there are no changes, no time can be defined. But it is also true that if space were not changing, no contours, we would not have a concept of space either. A total three dimensional uniformity would not register.

Our scientific time definition uses the concept of entropy to codify change in space, and entropy tells us that there exists an arrow of time.

In special relativity and general relativity time is defined as a fourth coordinate on par with the three space directions, with an extension to imaginary numbers for the mathematical transformations involved. The successful description of nature, particularly by special relativity, confirms the use of time as a coordinate on par with the space coordinates.

It is the arrow of time that distinguishes it in behavior from the other coordinates as far as the theoretical description of nature goes.