The unit of time on Earth that is based on the revolution around the sun is a year.

Here's why:

* Revolution: The Earth takes approximately 365.25 days to complete one full orbit around the sun. This is what we call a year.

* Calendar: We use this revolution to define our calendar year, which is roughly 365 days long. The extra quarter day is accounted for by leap years, which occur every four years.

So, the year is directly tied to the Earth's movement around the sun.