Phylum Nemertea, commonly known as ribbon worms, are a group of marine organisms known for their elongated, flattened bodies. They are distinguishable by their proboscis, a long, retractable tube used to capture prey, and their paired nerve cords that run along the length of their body. While "Phylum Nemertea" is the standard scientific name for this group, there are several other terms that can be used interchangeably, such as "ribbon worms," "proboscis worms," or "Nemertean worms." These synonyms highlight different aspects of Nemerteans' biology that make them unique and fascinating organisms to study.