In terms of the importance of the "first line of latitude", the equator has to come first.
The Tropic of Capricorn is a line of latitude.
The line of latitude between the Tropic of Cancer and Tropic of Capricorn is the Equator. It is located at (0^\circ) latitude and acts as the dividing line between the Northern and Southern Hemispheres.
The Tropic of Capricorn is a line of latitude, specifically, 23° 26′ 14″ South
It's roughly 23.5 degrees south of the equator, all the way around the Earth.
equator
a line of latitude
There is a major line of latitude located at 23.5 degrees south latitude, called the Tropic of Capricorn.
The line you are probably asking about is at 23.5 degrees South latitude, and it is called the Tropic of Capricorn.
The Tropic of Cancer is the parallel of the Tropic of Capricorn. The Tropic of Cancer is located at 23.5 degrees north latitude, while the Tropic of Capricorn is located at 23.5 degrees south latitude. These are the furthest points north and south where the sun can appear directly overhead.
Tropic of Capricorn
The Tropic of Capricorn runs through Paraguay. It is located at approximately 23.5 degrees south latitude.
The Tropic of Capricorn cannot be seen except on maps. It is only an imaginary line of latitude that marks the tropics.