Sink is a type of Move. Move is related to Come. Come is related to Join. Join is related to Membership. 
Reduction is a synonym of Fall. Fall is related to Stumble. 
Sink --IsA--> Move <--RelatedTo--> Come <--RelatedTo--> Join <--RelatedTo--> Membership 
Reduction <--Synonym--> Fall <--RelatedTo--> Stumble 