Hemichordata is a phylum of marine animals that are divided into two classes: Enteropneusta and Pterobranchia. However, there are several other terms used as synonyms for this phylum, including Acorn worms, Enteropneusts, and Graptolites. These names come from the unique characteristics of Hemichordates, such as their acorn-shaped bodies and their feeding structure, known as a pharynx. Hemichordates have been studied for their importance to evolutionary biology, as they have characteristics that link them to both Chordates and Echinoderms. Understanding the various synonyms used to describe this phylum can help researchers and scientists to more effectively communicate and learn about these fascinating marine animals.