Retia is a word that is not as commonly used in everyday language. It refers to a network of blood vessels or nerves. There are a number of synonyms that can be used in its place depending on the specific context. For instance, "plexus" can refer to a collection of nerves or blood vessels, and "meshwork" or "network" can describe a complex interlacing of these structures. "Confluence" can be a synonym for a meeting point or where these vessels or nerves all come together. Additionally, "plexus" and "web" can be used to describe the complex system of blood vessels and nerves that make up the human body.