Hat is a synonym of Lid. Lid is related to Cover. Cover is related to Duck. Duck can be used for Eat. 
Wood is related to Related. Related is related to Cost. Cost is related to Unit. Unit is etymologically related to Unity. 
Hat <--Synonym--> Lid <--RelatedTo--> Cover <--RelatedTo--> Duck --UsedFor--> Eat 
Wood <--RelatedTo--> Related <--RelatedTo--> Cost <--RelatedTo--> Unit --EtymologicallyRelatedTo--> Unity 