What is the left side of a ship called?

The left side of a ship or any floating vessel is called the portside, and the right is called starboardside.

When facing forward (that is in the direction the ship normally moves) on a ship (towards the bow, or pointy end); the left side of the ship is referred to as port. The right side is called starboard. The back of the ship is called the stern.

When facing the front of the ship, toward the bow, the left side is Port and the right side is Starboard.

Port is Left was the sign prominently placed on the Captain's cabin desk, as well as at the helm, for landlubbers that were working hard to be real sailors.