Nountropical year (plural Tropical years)
- The time that it takes for the Sun to return to the same position along the ecliptic, as viewed from the Earth, especially:
- A vernal equinox year, the time between two successive vernal equinoxes.
The vernal equinox tropical year of about 365.2424 years (varying over the centuries) is used for the Gregorian as well as earlier calendars, to keep the vernal equinox as close as possible to March 21st. This is different from the mean tropical year of 365.24219 days.