In radio communications, often communicators speak of a body sides using "starboard", "port", and "stern" sides. This is mainly due to the fixture of the words referring to each sides.
Similar to compass navigation system, "starboard", "port", and "stern" are fixed terms, like bearing values. A Starboard is always referring to the right side of the body, just like 90 degree is always referring to East.
If we use "left" or "right", we need to figure out the speaker's facing position. That is very confusing. a left can become a right if the speaker is facing in an opposite direction. Since radio communications require straight to the point, simple, stupid, clear, and short message, we can't afford to speak "left of ...." and let receiver to process.
That's the reason why these terms are available.
All 3 sides are divided evenly from a circle point of view.
That's all about body sides terms.