The apparent line that separates earth from sky. Learn more on Wikipedia.

Height Above Horizon

The vertical distance of an object or location above the horizon level. PhotoPills uses Height Above Horizon to adjust the calculations of sun and moon rise and set times. For example, an observer situated at the top of a mountain at 2.000 feet of height above his horizon will see sunrise earlier in the morning than another observer situated at the horizon level.

Hyperfocal Distance

The closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp. Learn more on Wikipedia.

Hyperfocal Near Limit

It is situated at half the hyperfocal distance. If we focus at the  hyperfocal distance, we'll get sharpness from the Hyperfocal Near Limit to infinity.

Horizontal Angle of View

Angle of view  measured horizontally (from the left to right edge of the frame).

Horizontal Field of View

Field of view measured horizontally (from the left to right edge of the frame).