cell wall Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a rigid outer layer of plant cells that provides support and protection. Example Sentence He studied the cell wall through the microscope. More Example Sentences It protects the plant from damage and disease. Synonyms membrane; barrier; protective layer Hear It! Say It! Write It! cell wall Switch to cursive Start Share with your friends: