That statement is incorrect. Altitude is not defined as the distance in degrees of a star below the horizon. Here's why:

* Altitude is the angular distance of a celestial object (like a star) above the horizon. It's measured in degrees, with 0 degrees being the horizon and 90 degrees being directly overhead (zenith).

* Distance below the horizon is not a standard astronomical term.

To clarify:

* If a star is above the horizon, it has a positive altitude.

* If a star is below the horizon, it has a negative altitude.

The term you might be thinking of is depression, which refers to the angular distance of an object below the horizon. However, depression is less commonly used than altitude.