prefixes Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition plural noun. groups of letters added to the beginning of a word. Example Sentence I can add different prefixes to words. More Example Sentences Prefixes help to form new words. Synonyms affixes; additions Antonyms suffix Hear It! Say It! Write It! prefixes Switch to cursive Start Share with your friends: