The word "skull" is commonly used to refer to the bony structure that encloses the brain in animals, including humans. However, there are various synonyms for this word that can be used to add variety and depth to your writing. Some examples of such synonyms include cranium, head, braincase, bonebox, and noggin. These words offer a unique way of referring to this important part of the body, and can help you avoid redundancy in your writing. Whether you are a writer, a student, or just someone who is interested in language, it is always useful to expand your vocabulary and explore the different ways in which you can express yourself.