I suppose they could be called a pair, just like two horizontal lines could be called a pair, but it's not a "mathematical" or "technical" term.
The horizontal line is called the horizontal axis
It is called the displacement in the horizontal direction.
the horizontal axis for chart is called X-axis.
because they are parallel to the plane of the horizon
The sport of horse racing over jumps is called steeplechasing, while racing with no jumps is called flat racing.
*Why are jumps called jumps?In order to clear an "obstacle" of any sort, a horse must jump over it. Therefore these "obstacles" became known as jumps.
A horizontal mine entrance is called an adit. It is a nearly horizontal passage from the surface into a mine for access or drainage.
It is called a bounce.
plank
When a whale jumps out of the water it's called Breeching
The horizontal distance between two successive crests is called the wavelength. It is a measure of the length of one complete cycle of a wave and is commonly represented by the symbol λ.
It is called a horizontal line!
I suppose they could be called a pair, just like two horizontal lines could be called a pair, but it's not a "mathematical" or "technical" term.
The horizontal line is called the horizontal axis
It is called the displacement in the horizontal direction.
they are called Horizons.