👉 The word "Cinder Block" refers to a fictional character from J.R.R. Tolkien's Lord Of The Rings series. The term "cinder block" means a large, hard, brick-like substance used in construction and architecture. The definition of "cinder block," as given by Tolkien, is that it represents the hardness of stone and is associated with a rough surface that gives it a smooth appearance when polished, often due to the presence of organic matter like minerals. The term is also often used metaphorically to describe something hard or tough.