The occipital bone is located at the lower back of the skull.
Tips
memory
Brilliant naming logic: 枕 ('pillow') + 骨 ('bone') = 'pillow bone' — the bone that rests on the pillow when you sleep. Way more intuitive than the Latin 'occipital'. Once you see this, you'll never forget it.
usage
Anatomy/medical term. Appears in textbooks and forensic/medical contexts. Less common in everyday speech — for casual 'back of head' use 后脑勺 (hòunǎosháo).