The time for the earth to make one revolution around the sun, measured between two vernal equinoxes.
Period of time for the ecliptic longitude of the Sun to increase 360°
1
And now, by a variety of indications, it was manifest that the winter of the tropical year was at hand.
2
It also approximates a tropical year, the time it takes for the Earth to complete a full orbit around the sun.
3
It was now the spring of the tropical year: the deciduous trees were renewing their verdure, and were covered with young shoots, and bursting leaf-buds.