A double room usually refers to two people occupying the same room.
A double bed room usually means that there are two beds in the room with either two double sized beds or two queen sized beds in it.
A single room usually refers to a room that one person occupies. It can contain a single/twin sized bed, a double sized bed, a queen sized bed or a king sized bed.
A twin bed room refers to a room with a twin sized bed in it and it's usually for a single individual.
A suite usually refers to a room with an adjoining living room to it. It is larger then your standard room and has more amenities.
A deluxe room usually refers to a room a little larger then a standard room, but smaller then a suite.
I hope that this helps somewhat and I am sure that I have confused you even more. Since hotels have different terms and definitions for their rooms, I owuld call the hotel that you plan to stay in to ask them.
I do know this though, suites cost the most amount of money followed by deluxe rooms and then your standard rooms.