Periosteum
The periosteum is a dense membrane composed of fibrous connective tissue that closely wraps (invests) all bone, except that of the articulating surfaces in joints which are covered by a synovial membrane.
'Peri-' is a prefix borrowed from the Greek meaning 'around or about' and '-osteum' also comes from the Greek, from 'osteon' meaning 'bone', so periosteum literally means 'around the bone.'