'periodontitis' originates from Greek, specifically the elements 'peri-' + 'odont-' and the suffix '-itis', where 'peri-' meant 'around', 'odont' meant 'tooth', and '-itis' meant 'inflammation'.

'periodontitis' was formed in New/Modern Latin from Greek roots and entered medical English usage via Neo-Latin; the compound combined 'peri-' + 'odont-' + '-itis' to name inflammation around the tooth-supporting tissues.

Initially, it literally meant 'inflammation around a tooth'; over time it became the established medical term for the bacterial, often chronic disease affecting the periodontium and leading to tissue and bone loss.