Sweater is related to Sleeve. Elbow is part of Sleeve. Elbow is related to Body. Body is related to Exercise. 
Boat is a synonym of Ship. Ship is related to Line. Line is related to Front. Front is a different concept from Profile. 
Sweater <--RelatedTo--> Sleeve <--PartOf-- Elbow <--RelatedTo--> Body <--RelatedTo--> Exercise 
Boat <--Synonym--> Ship <--RelatedTo--> Line <--RelatedTo--> Front <--DistinctFrom--> Profile 