Sky can be used for Dream. Sky is related to Big. Big is related to Leap. 
Grandchild is the opposite of Grandparent. Grandparent is a type of Animal. Game is a type of Animal. 
Dream <--UsedFor-- Sky <--RelatedTo--> Big <--RelatedTo--> Leap 
Grandchild <--Antonym--> Grandparent --IsA--> Animal <--IsA-- Game 