Elevator is a type of Room. Bathroom is a type of Room. you are likely to find Bathroom in/at/on House. you are likely to find Lamp in/at/on House. 
Retail is a type of Sell. Sell is related to Profit. Profit is related to Company. Company is related to Partnership. 
Elevator --IsA--> Room <--IsA-- Bathroom --AtLocation--> House <--AtLocation-- Lamp 
Retail --IsA--> Sell <--RelatedTo--> Profit <--RelatedTo--> Company <--RelatedTo--> Partnership 