A<unk>  is a hemorrhage of blood between the skull and the periosteum of a newborn baby secondary to rupture of blood vessels crossing the periosteum.  Because the swelling is subperiosteal its boundaries are limited by the individual bones, in contrast to a chignon.
Cephalhematoma
Subgaleal hemorrhage
Encephalocele
Subdural hygroma
Cementoblastoma
Acrospiroma
Sterculia
Sebaceoma