A pier is like a big wooden or concrete walkway that juts out into the water. It's like a long line of planks or blocks that are fixed together and supported by sturdy structures underwater.
People use piers for different reasons. Some go fishing or crabbing off the end of the pier, others go for walks or runs, or to just enjoy the views. Boats might even come up to a pier to drop off or pick up passengers.
A pier can be found in many bodies of water like the ocean, lakes, and rivers. They can be really long or short, depending on where they are built and what they are for. Some piers are so long that they feel like they stretch on forever!