Receiving is generally defined as a single act, while concealing, possessing, buying, and transferring are conceived of as continuing acts. Fencing or trafficking are the continuing acts of being a middleman or distributor. Control of the property can be actual or constructive, and it's the material fact of the item being stolen that matters, not the belief that it's stolen. If someone hides something they think is stolen, but it is not in fact stolen, then they have not received anything stolen. This lowered culpability requirement is aimed at junk dealers and pawnbrokers.
Robbery is forceful stealing and extortion is blackmail.
Robbery is the most common crime in the United States. Only a slight movement of the property is necessary to fulfill this requirement if the element of impossibility is present or the threat of harm accompanies the taking. Victims must relinquish their property because they honestly and reasonably fear the robbers' threats. The victim is compelled to acquiesce in the taking of the property. Other rooms in the house in which the victim is located is considered within their presence.