periodontium per·i·o·don·ti·um (pěr'ē-ə-dŏn'shē-əm)
n. pl. per·i·o·don·ti·a (-shē-ə, -shə)
The tissues that surround and support the teeth, including the gums, cementum, periodontal ligament, and alveolar and supporting bone. Also called alveolodental membrane, peridental membrane.