horizontal
If a line is horizontal, it goes from left to right or from right to left.
A plane is horizontal if it’s perpendicular to the general direction of gravity.
The horizon is horizontal.
The opposite of horizontal is vertical.
If a line is horizontal, it goes from left to right or from right to left.
A plane is horizontal if it’s perpendicular to the general direction of gravity.
The horizon is horizontal.
The opposite of horizontal is vertical.