According to Albert Einstein's theory of relativity, time is indeed considered a physical dimension. It is interconnected with space to form what is known as the space-time continuum. In this framework, time is not separate from space but rather a part of the fabric of the universe.
When we measure time using units such as seconds, minutes, or hours, we are quantifying the passage of time or the intervals between events. These units provide a standard way to compare the durations of different events or processes. We can think of it as measuring the "speed of time" in a sense, but it is more accurate to say that we are measuring the duration or temporal intervals between events.
Einstein's theory of relativity also introduced the concept of time dilation, which states that the passage of time is not absolute but can vary depending on the relative motion of observers and the strength of gravitational fields. This means that time can appear to pass differently for different observers in different situations.
In summary, time is a physical dimension, and when we measure time, we are quantifying the intervals or durations between events rather than measuring the speed of time itself.