Here are some questions alway pop up in my mind whenever I try to book a hotel room during vacation. Finally, I have found some explanation from the internet.

Q. What is the difference between the following room types and occupancy categories? Single, Twin, Double, Triple, Family, Quad, Suite, Apartments

Room Type:
Single - Room has 1 single bed, strictly for 1 adult only. No extra bed will fit.
Twin - Room has 2 single beds to accommodate 2 adults. A third adult will require an extra bed.
Double - Room has 1 large (Queen or King sized) bed to accommodate 2 adults. A third adult will require an extra bed.
Double for Single Use - Room has 1 large (Queen or King sized) bed to accommodate 1 adult only.
Triple - Room has either 3 single beds, or 1 large (Queen or King sized) bed and 1 single bed, or equivalent beds to accommodate 3 adults.
Family / Quad - Room has either 4 single beds, or 1 large (Queen or King sized) bed and 2 single beds, or equivalent beds to accommodate 4 adults. Typically, no extra bed will fit.
Junior Suite / Suite - consists of a bedroom and a small living room to accommodate 2 adults, unless otherwise is specified . A third adult will require an extra bed.
All of the above room types have an attached toilet and shower/bath, unless otherwise is specified.

Hotel Apartment / Serviced Apartment Types:
1 Bedroom Apartment - 1 Bedroom with a small living room, kitchenette and 1 toilet to accommodate 2 adults, unless otherwise is specified. A third adult will require an extra bed.
2 Bedroom Apartment - 2 Bedrooms with a living room, kitchenette and 1 toilet to accommodate 4 adults, unless otherwise is specified. A fifth adult will require an extra bed.
3 Bedroom Apartment - 3 Bedrooms with a living room, kitchenette and 1 toilet to accommodate 6 adults, unless otherwise is specified . A seventh adult will require an extra bed.

Q. What is the difference between these room categories - Standard, Superior and Deluxe?
This varies from one hotel to another. The main difference is determined by the room floor size. A typical Standard Room has a smaller floor area compared to a Superior or a Deluxe Room.
Please note that some hotels can only accommodate requests for additional beds in their Superior and Deluxe Rooms.