There are multiple definitions:

1. atrial refractory period(English)

   • Cardiology, Electrophysiology

2. absolute refractory period(English)

   • RRP
   • Electrophysiology, Physiology

3. alternative rites of passage(English)

4. acute radiation pneumonitis(English)

   • an inflammatory reaction that appears in the high-dose irradiated portion of the lungs after the completion of EBRT
   • EBRT
   • Pulmonology, Radiotherapy /radiation, Oncology
   • https://doi.org…-3993-8.00026-X

5. abnormal relaxation pattern(English)

   • RFP
   • Cardiology
   • https://doi.org…2167(03)00003-9