Fundament is a noun that refers to the essential foundation of an idea, system, or structure. Synonyms for this word can include cornerstone, basis, bedrock, groundwork, and foundation. Each of these terms emphasizes the critical nature of the support provided by the fundament to the overall structure. A cornerstone is the fundamental starting point of a building, while bedrock emphasizes the immovable, stable qualities of the foundation. Groundwork emphasizes the preparatory work required for the construction of a strong structure. Finally, foundation refers to the fundamental elements necessary for something to exist and grow. All of these synonyms suggest the importance of the fundament to the overall success of any endeavor.