There are multiple definitions:

1. proportional incidence rate(English)

   • Epidemiology

2. postisometric relaxation [technique](English)

   • CRAC, CR, LT, MT, PA, RI, SA, UT
   • Physical therapy, Rehabilitation, Shoulder and other joints
   • https://doi.org…55/2022/2537957

3. Parent Infant Relationship(English)

   • refers to infancy predictors of psychopathology in the second year of life
   • CCC, DC, DC:0-3R, ERA, ITSCL, MEI, PC, PIR, PIR-GAS
   • Communication
   • https://doi.org…10.2007.01860.x

4. photoplethysmogram intensity ratio(English)

   • ratio of maximum and minimum amplitude of the pulse signal, recorded as its mean value
   • AASI, BP, ECG, MAP, PP, PPG, PTT
   • Ratio-based metric, Signal analysis
   • https://doi.org…BC.2015.7318383

5. poverty-income ratio(English)

   • SES
   • Social aspects, Ratio-based metric, Mental health
   • https://doi.org…888-023-05156-2

6. pyroelectric infrared(English)

   • may refer to motion sensor
   • GTCS, HCVR, SUDEP
   • Photonics, Monitoring, Sleep medicine, Epilepsy or syncope
   • https://doi.org/10.1113/JP288697