I'll give it a shot:
Catagory
Class
Type Rating.
In decending order.
Catagory:
(1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a broad classification of aircraft. Examples include: airplane; rotorcraft; glider; and lighter-than-air;
Class:
(1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a classification of aircraft within a category having similar operating characteristics. Examples include: single engine; multiengine; land; water; gyroplane; helicopter; airship; and free balloon;
Type:
(1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a specific make and basic model of aircraft, including modifications thereto that do not change its handling or flight characteristics. Examples include: DC–7, 1049, and F–27; and
So lets break down the B747
Catagory: Airplane
Class: Multi engine Land
Type: Boeing 741 thru 748 EI 747-200, 400 etc
In the USA being that the aircraft is over 12,500 lbs (5700 kg in other parts of the world) you need a type rating.
Now your type rating can denote limitations....Example: Second in Command, Circling in VMC etc.
Remember Catagory then Class then Type.