Poor SP was really distraught about it, because it apparently is synonymous with an engineering term.
I was not distraught, you and others went ape when I pointed out that in engineering and per dictionaries, and per english language rules and syntax the word simply means an imaginary line sighted visually. As such it does not mean you actually see anything, or that you have any limit on distance, such as say a star. The AMA defines if for their use, Congress did not.