A division ran right across the image, from one edge to the other like a horizon line.
The horizon line was a deep blue edging into space black.
The sun had been resting on the horizon line of clouds for a long moment.
It may be found along one of the circular "horizon" lines.
After a minute or so, Kirk thought he noticed something near the horizon line.
The top bar of the Z is the gray horizon line.
A bare gray surface is left as sky at the horizon line.
The horizon line rose and the angle of it altered.
The movements tend to be circular, and there is always a horizon line.
Perspective drawings have a horizon line, which is often implied.