Definitions

[surfman]

DrNip » 02 Jan 2014, 13:04[/url]"]Pretty much sums it up here I think:

A jon boat (or johnboat) is a flat-bottomed boat constructed of aluminum, fiberglass, or wood with one, two, or three bench seats. They are suitable for fishing and hunting. The hull of a jon boat is nearly flat, therefore it tends to ride over the waves rather than cut through them as a V-hull might, thus limiting the use of the boat to calmer waters. Jon boats typically have a transom onto which an outboard motor can be mounted. They are simple and easy to maintain, and inexpensive with many options to upgrade. Typical options might include live wells/bait wells, side or center consoles, factory installed decks and floors, electrical wiring, accessory pads/mountings, casting and poling platforms.
Jon boats with beefed up aluminum construction, and powered by jet-drive outboards, are capable of operating in extremely shallow water and thus are used frequently in rocky rivers and areas with submerged obstructions such as oyster bars and coral.
Jon boats are available commercially between 8 and 24 feet (2.4 and 7.3 m) long and 32 to 60 inches (81 to 150 cm) wide, though custom sizes may be found. The simple design includes an open hull, without a bilge, leaving the ribs exposed. Many individuals choose to cover the ribs, producing a flat, level surface.

This, jon boats were made out of wood long before they were made out of aluminum.
Probably called somthing else then.
Plastic is a newer material so now they are available in wood, metal, plastic(fiberglass too). A rectangular flat bottom boat is a jon, just that simple, you can vary that design of course many ways but, the basic concept it a rectangular flat bottomed boat.