A wharf is a solid built platform at the edge of water, made so ships and boats can come right up to it, tie on, and load or unload. Think of the flat stone or wooden area where the goods sit, the trucks drive up, and the workers move boxes — that is the wharf. It is usually built along the shore or sticking out into the water, and it is strong enough to carry heavy things. The word is old and a bit heavy-sounding. In everyday English today, many people would just say "the dock" or "the pier", and those words overlap so much that ordinary speakers do not keep them apart carefully. If you want the careful difference: a pier is usually a narrow thing walking out into the water, often for people to stroll on; a dock can mean the water space where the ship sits as well as the structure; a wharf is the working platform along the side where cargo is handled. But do not trust that people follow this. "Wharf" survives strongly in place names — Canary Wharf in London, Fisherman's Wharf in San Francisco — and in writing about shipping and old sea life. The plural is unusual: both "wharves" and "wharfs" are correct, with "wharves" more common.