Port is related to Boat. Boat is related to Engine. Engine is part of Automobile. Automobile is related to Car. 
Grandfather is a type of Grandparent. Grandparent is the opposite of Grandchild. Grandchild is the opposite of Grandmother. Grandmother is a type of Person. 
Port <--RelatedTo--> Boat <--RelatedTo--> Engine --PartOf--> Automobile <--RelatedTo--> Car 
Grandfather --IsA--> Grandparent <--Antonym--> Grandchild <--Antonym--> Grandmother --IsA--> Person 