Interest is related to Loan. Loan is a different concept from Lend. Lend is the opposite of Borrow. 
Prison is related to Cage. you are likely to find Feather in/at/on Cage. 
Interest <--RelatedTo--> Loan <--DistinctFrom--> Lend <--Antonym--> Borrow 
Prison <--RelatedTo--> Cage <--AtLocation-- Feather 