Stock is a synonym of Inventory. Inventory is a type of List. Key is a type of List. 
Child can be used for Teaching. Teaching is related to Class. Class is a synonym of Distribute. Assign is a type of Distribute. 
Stock <--Synonym--> Inventory --IsA--> List <--IsA-- Key 
Child --UsedFor--> Teaching <--RelatedTo--> Class <--Synonym--> Distribute <--IsA-- Assign 