Pen is related to Poet. Poet is related to Profession. Profession is related to Singer. Voice is a type of Singer. 
Costume is related to Dress. Dress is related to Party. 
Pen <--RelatedTo--> Poet <--RelatedTo--> Profession <--RelatedTo--> Singer <--IsA-- Voice 
Costume <--RelatedTo--> Dress <--RelatedTo--> Party 