Other forms: skulls
The bones of a person's or animal's head make up the skull. All vertebrates have a skull. Pirate flags often feature a human skull and crossbones (because a parrot skull wouldn’t be nearly so scary).
The wide-eyed head of a skeleton is its skull. Skulls are hard and bony, but they're a little bit flexible as well—characteristics that help them protect the brain they enclose. Your skull consists of two parts: the bones of your face and the neurocranium, or "braincase." The precise origin of skull is uncertain, but it probably traces back to the Old English scealu, "husk or shell."