Middle is a different concept from Begin. Begin is the opposite of Conclude. 
Selection is a synonym of Number. Number is related to Used. Used is related to Coal. Coal is related to Diamond. 
Middle <--DistinctFrom--> Begin <--Antonym--> Conclude 
Selection <--Synonym--> Number <--RelatedTo--> Used <--RelatedTo--> Coal <--RelatedTo--> Diamond 