"Rattle-top" is a unique word that refers to a plant species with a characteristic rattling sound that its seeds make inside its dried pods. However, there are few synonyms for this specific type of plant. Some common alternatives to "rattle-top" include "shaking grass," "skeleton weed," and "bouncing bet." These plants all share a similar characteristic of making a rattling noise when moved or dried, but they differ in their appearance and geographical region. "Shaking grass" is predominantly found in North America, while "skeleton weed" is native to Europe and Asia. "Bouncing bet," on the other hand, is a common name for a plant species found in the Mediterranean region.