Stair is related to Ladder. Ladder is a type of Degree. Degree is a synonym of Point. 
Ground is related to Level. Level is related to Orientation. Landmark can be used for Orientation. Landmark is related to Hill. 
Stair <--RelatedTo--> Ladder --IsA--> Degree <--Synonym--> Point 
Ground <--RelatedTo--> Level <--RelatedTo--> Orientation <--UsedFor-- Landmark <--RelatedTo--> Hill 