Planarians are fascinating creatures found in freshwater bodies across the world. These flatworms have some unique characteristics that make them quite interesting to study. If you're looking for synonyms for the word "planarians," you could use terms like flatworms, turbellaria, or triclads. Another synonym for planarian that you might consider using is Catenulida, which refers to a group of small, marine flatworms that share some features with planarians. Regardless of what term you choose to use, it's clear that these creatures are a fascinating subject of study for scientists and nature enthusiasts alike.