Ass is related to Association. Association is related to Tribe. Tribe is related to Reservation. 
Railroad is related to Long. Long is a synonym of Deep. Deep is related to Cut. French is a type of Cut. 
Ass <--RelatedTo--> Association <--RelatedTo--> Tribe <--RelatedTo--> Reservation 
Railroad <--RelatedTo--> Long <--Synonym--> Deep <--RelatedTo--> Cut <--IsA-- French 