Friend is a different concept from Stranger. Stranger is the opposite of Fellow. Fellow is a synonym of Boyfriend. Boyfriend is a type of Lover. 
Leg is related to Waist. Waist is a type of Area. Area is related to Shade. 
Friend <--DistinctFrom--> Stranger <--Antonym--> Fellow <--Synonym--> Boyfriend --IsA--> Lover 
Leg <--RelatedTo--> Waist --IsA--> Area <--RelatedTo--> Shade 