What is the difference between a dock, port, quay, harbour, jetty and a wharf?

A dock is dug out and usually has gates so that the water level is kept up even though the tide has gone out. Access may only be at certain times of the tide. A dock is for mooring ships for cargo or passenger exchange, or sometimes repair. A dry dock can have the water evacuated so the ship rests on the bottom for easy access to the hull. A harbour may be natural or partly dug out, or even made with floating materials. It doesn't have gates, but may have a narrow entrance. Provides safe anchoring or mooring for ships. A quay is the built up bank of a harbour or dock where ships can moor. A jetty is a sort of pier sticking out either to provide shelter for shipping, or short term mooring in deep water for ships that cannot approach the shore - such as liners and oil tankers. Can also be smaller and for ferry connections, etc. A wharf is less substantial than a quay, and may be on the bank of a river. Wharf also applies to certain sandy banks such as Mad WHarf and Mockbeggar wharf which most certainly are not suitable for shipping.

Dock (maritime), an area of water for building or repairing or loading and unloading ships or ferries

A port is a facility for receiving ships and transferring cargo.

A quay, pronounced 'kay', 'key' or 'kway', is a wharf or bank where ships and other vessels are loaded.

A harbor or harbour or haven, is a place where ships may shelter from the weather or are stored.

A jetty is a structure, such as a pier, that projects into a body of water to influence the current or tide or to protect a harbor or shoreline from storms or erosion.

A wharf is a fixed platform, commonly on pilings, where ships are loaded and unloaded.

https://en.wikipedia.org/wiki/Dock
https://en.wikipedia.org/wiki/Harbour
https://en.wikipedia.org/wiki/Quay
https://en.wikipedia.org/wiki/Port

The jetties I've seen are the ones built over a hundred years ago near the mouth of the St. Johns River in Jacksonville, FL, and the one near the port of Valdez, AK. Both are long strips of riprap jutting, or jetting, into the sea to protect the harbor.

https://en.wikipedia.org/wiki/Jetty

For many Americans, a "dock" is an often ramshackle wooden platform extending over a lake or river. I grew up across the street from a river and some of the neighbors had docks to fish from or launch their boats from. When playing with their children, the standard order was, "Stay off the dock!" You can see this kind of dock in "On Golden Pond," filmed at Squam Lake, NH.