In a school staffing context, PET stands for Physical Education Teacher — the teacher responsible for physical education, sports and games periods. The same three letters can mean a Physical Efficiency Test in recruitment, so the meaning depends on the setting. In most schools, 'the PET' simply refers to the games teacher.
In Indian schools
A PET is a staff member like any other on the rolls, linked to the batches and periods they take. RaivatEdu models staff with role-based access, so a games teacher's account can be scoped to just what their role needs.