Tethyidae is a family of marine sponge species belonging to the phylum Porifera. Synonyms for Tethyidae include Tethyida, Tethyidae Gray, 1867, and Tethydaeidae. These sponges have a slimy texture and are found in deep, cold water environments, where they play an essential role in the food chain. The family Tethyidae has diverse varieties and has a significant impact on marine ecosystem health. Scientists have studied these sponges for their potential medicinal properties, including the ability to fight cancer tumors. Understanding the synonyms for Tethyidae helps researchers and marine biologists to identify and study these sponge species, their ecological interactions, and their potential therapeutic applications.