There are multiple definitions:

1. low-pass filter(English)

   • HPF
   • Filtering (of signals)

2. Late Parasitological Failure(English)

   • AL, DP, ETF
   • Malaria, Parasitology
   • https://doi.org…475-2875-10-198

3. lesser palatine foramen(English)

   • CBCT, GIM, GPF, LPC, PPF
   • Anatomy, ENT
   • https://doi.org…276-019-02179-x