fibres Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a slender threadlike structure that combines with others to form animal or vegetable tissue; A food substance that provides bulk Chiefly British. Example Sentence The ropes where made from oakum fibres. Synonyms thread; cord; string Antonyms bone Hear It! Say It! Write It! fibres Switch to cursive Start Share with your friends: