Counter is a type of Register. Register is related to Class. Freshman is a type of Class. 
Availability is related to Supply. Water is a type of Supply. Water is related to Sail. Sail is a synonym of Sweep. 
Counter --IsA--> Register <--RelatedTo--> Class <--IsA-- Freshman 
Availability <--RelatedTo--> Supply <--IsA-- Water <--RelatedTo--> Sail <--Synonym--> Sweep 