waterwheel Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a machine powered by flowing or falling water. Example Sentence The old mill had a large waterwheel that was still functional. Synonyms water mill; hydroelectric generator; turbine Antonyms windmill; solar panel Hear It! Say It! Write It! waterwheel Switch to cursive Start Share with your friends: