What is another word for river boulder?
Pronunciation: [ɹˈɪvə bˈə͡ʊldə] (IPA) 
River boulders are large and heavy rocks that can be found in riverbeds or on riverbanks. These boulders can range in size from small pebbles to huge boulders that are several feet in diameter. Some of the synonyms for the term river boulder include stones, rocks, pebbles, and cobbles. Stones and rocks are both commonly used to describe river boulders of various sizes. Pebbles are smaller river boulders that are typically less than 2.5 inches in diameter. Lastly, cobbles are round river boulders that are larger than pebbles, but smaller than larger boulders. No matter which term you use, river boulders are an important part of many environments and can have a significant impact on the landscape around them.
