Spektor,
A 'boogie' is a dance you do to music!
A 'bogie' is one of many terms for a part of a vehicle with wheels arranged in a set. Railway carriages and large aircraft sometimes have 'bogies'. Some American manufacturers prefer the term 'truck'. More generically, any wheel assembly, or the whole system, on an aircraft is referred to in America as the 'gear' whereas in the United Kingdom and some other places it's called the 'undercarriage'.
Now, all models of B747 have 4 main gear legs, each terminating in a truck with 2 axles, with 2 wheels on each. The 2 outer legs are attached to the main spar on the inboard portion of the wing and the 2 inner legs are attached to the fuselage and are known as the 'body gear'. The body gear is aft of the wing gear. The body bogies or trucks have some limited steering capability. I've seen a 747 land with one body leg 'hung up' or not deployed - not a big drama - in that the aircraft was able to vacate the runway and taxi to stand. At a heavier weight, no doubt the additional loads placed on the wing gear by one body leg missing would put too much loading on the tyres on that side. I've also seen a 747 with the oleo seals on a body leg burst, so there was effectively no weight on those wheels - again no real drama for landing and vacating, except for all the tyres locking up every time the brakes were applied during taxying, huge clouds of smoke!
The A340 has 2 legs attached to the wings and one centreline body leg, like the DC10-30 and variants. Again, this is required to support departure masses but the 2 main legs can support landing stresses - I've witnessed that, too, no problems.
Having an aircraft arrive with any leg retracted that is normally used is regarded as an Emergency by us ground types and we react accordingly, despite being aware that the manufacturers have made allowances for this operation. We regard it as being similar to an overweight landing, in that any tyre problem is likely to have greater consequences than a tyre problem within Standard Operating Procedures.
Good luck
The Odd One