There are many such lines, they are called lines of longitude.
The imaginary line drawn through the center of the Earth around which Earth rotates is called the axis. This axis is tilted at an angle of approximately 23.5 degrees relative to the plane of Earth's orbit around the Sun, which causes the changing of seasons.
In the globe it is called the axis. In a sphere it is called the diameter.
They are called the Arctic Circle and the Antarctic Circle.
The imaginary line drawn perpendicular to the surface at the point of incidence is called the normal. It serves as a reference for measuring the angle of incidence and the angle of refraction in the study of optics, particularly when light travels through different mediums and changes direction.
The Demarcation Line was an imaginary line passing through the continent of South America. It was drawn by Pope Alexander VI to divide the new lands conquered by Portugal from those of Spain.
The straight line between the poles is the Earth's axis of rotation. The curved lines between the poles and along the surface are the meridians of longitude.
The line is called the principal axis. It passes through the center of curvature and focus of the mirror.
Oh, dude, that imaginary line is called the Prime Meridian. It was drawn through South America to mark the 0 degrees longitude, like the starting point for all those fancy map coordinates. So, yeah, it's basically the center of the world, or at least the center of the map.
It's called the normal.
normal
Center of curvature !.*-Puro Sinaloa- *.! tt(-.-t)
normal