Thigh is the opposite of Breast. Breast is a synonym of Heart. Heart is a type of Muscle. Muscle is related to Meat. 
Letter is a type of Write. Letter can be used for Marketing. 
Thigh <--Antonym--> Breast <--Synonym--> Heart --IsA--> Muscle <--RelatedTo--> Meat 
Write <--IsA-- Letter --UsedFor--> Marketing 