PAP (pap), Acronym for peroxidase antiperoxidase complex. Abbreviation for 3′-phosphoadenosine 5′-phosphate. See: PAP technique. pap (pap), A soft food (for example, breadcrumbs soaked in milk or water). pap 1 any soft, soggy food. 2 porridge or gruel. PAP 1. Pap smear. 2. Peak airway pressure. 3. Peroxidase-antiperoxidase technique, see there. 4 …