What side of a vessel is opposite to the starboard side?

The side of a vessel that is opposite to the starboard side is called the port side. In nautical terms, the starboard side is the right side of the ship when you are facing forward towards the bow (the front of the vessel), while the port side is the left side. This terminology is crucial for navigation and safety on the water, as it helps to avoid confusion when giving directions or instructions, especially in emergency situations. The use of "port" and "starboard" provides a clear and standardized way to communicate about the position and orientation of the vessel.

The other terms refer to different aspects of the vessel: the bow is the front, and the stern is the back. While "starboard" simply restates one of the terms involved, it does not answer the question since it pertains to the same side rather than the opposite.