exoplanets Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. planets that orbit stars outside our solar system. Example Sentence Scientists are constantly discovering new exoplanets in our universe. Synonyms extraterrestrial planets; alien planets; extrasolar planets Antonyms Earth; Mars Hear It! Say It! Write It! exoplanets Switch to cursive Start Share with your friends: