Heart is a synonym of Center. Center is a type of Class. Class is related to Chemistry. Chemistry is a different concept from Biology. 
Economy is a type of Efficiency. Efficiency is a type of Ratio. Ratio is similar to Proportion. Proportion is etymologically related to Portion. 
Heart <--Synonym--> Center --IsA--> Class <--RelatedTo--> Chemistry <--DistinctFrom--> Biology 
Economy --IsA--> Efficiency --IsA--> Ratio <--SimilarTo--> Proportion --EtymologicallyRelatedTo--> Portion 