Trail is a type of Protein. Trail is a synonym of Track. Track is a type of Belt. 
Heaven is the opposite of Nightmare. Nightmare is a synonym of Horror. Horror is related to Genre. Genre is related to Comedy. 
Protein <--IsA-- Trail <--Synonym--> Track --IsA--> Belt 
Heaven <--Antonym--> Nightmare <--Synonym--> Horror <--RelatedTo--> Genre <--RelatedTo--> Comedy 