I think this is one of those bits of terminology that tends to be quite region-specific. In the US, my impression (from having lived near lots of lakes, rivers, and oceans in several different parts of country, and from looking at a lot of maps for various reasons) is that "dock" is probably the most-used general-purpose term (can pretty much be used, at least colloquially, for anywhere boats dock, where dock is a verb), with pier, wharf, jetty, and quay all still in use, but usually referring to specific sub-types of structures (pier, wharf, jetty) and/or much more localized (quay).