Subject is a synonym of Matter. Matter is related to Gray. Gray is related to Iron. Iron is related to Age. 
Pitcher is related to Throw. Throw is a type of Move. Move is a type of Propose. Propose is related to Suggestion. 
Subject <--Synonym--> Matter <--RelatedTo--> Gray <--RelatedTo--> Iron <--RelatedTo--> Age 
Pitcher <--RelatedTo--> Throw --IsA--> Move --IsA--> Propose <--RelatedTo--> Suggestion 