tri Get Printable Handwriting (tri) 1 syllables Hear It! Say It! Write It! Learn It! Spelling Test Definition prefix. a combining form meaning three used in the formation of compound words Example Sentence The tri in triangle changes the meaning of angle to three angles. Synonyms three; 3; prefix meaning three Antonyms four Hear It! Say It! Write It! tri Switch to cursive Start Share with your friends: