Refrigerator is related to Egg. Egg is related to Grocery. Food is a type of Grocery. Food is related to Item. 
Mother is related to Child. Childhood is derived from Child. 
Refrigerator <--RelatedTo--> Egg <--RelatedTo--> Grocery <--IsA-- Food <--RelatedTo--> Item 
Mother <--RelatedTo--> Child <--DerivedFrom-- Childhood 