What is the definition of tromosphere?

You're likely thinking of troposphere, not tromosphere. The troposphere is the lowest layer of Earth's atmosphere. Here's its definition:

Troposphere: The lowest layer of Earth's atmosphere, extending from the surface to about 7-15 kilometers (4.3-9.3 miles) in altitude. It is characterized by:

* Decreasing temperature with altitude: This is known as the environmental lapse rate.

* Presence of weather: Nearly all weather phenomena, like clouds, rain, snow, and wind, occur in the troposphere.

* Contains most of the atmospheric mass: The troposphere holds about 80% of the Earth's atmospheric mass.

* Contains most of the atmospheric water vapor: This is crucial for the formation of clouds and precipitation.

Let me know if you have any other questions!