- PTR-MS
- PTSD
- PUE
- PV diagram
- PVC
- PVC pipe
- PVD
- PVM
- PW4000
- PWM
- PWR
- PXI
- PXR
- PaaS
- Paan
- Pace
- Pacemaker
- Pacific Decadal Oscillation
- Pacific Ocean
- Pacific Rim
- Pacific-Antarctic Ridge
- Pacing
- Pacinian corpuscles
- Pack ice
- Pack-year
- Package
- Package diagram
- Packages
- Packaging waste
- Packed bed
- Packer
- Packet
- Packet Tracer
- Packet analyzer
- Packet forwarding
- Packet loss
- Packet switching
- Packing
- Packing density
- Packing dimension
- Packing problems
- Packstone
- Paclitaxel
- Paclobutrazol
- Padding
- Paddle
- Paddle wheels
- Paenibacillus polymyxa
- Page cache
- Page fault
- Page replacement algorithm
- Page view
- PageRank
- Paging
- Pagodas
- Paillier cryptosystem
- Pails
- Pain
- Pain management
- Paint
- Paint robot
- Paint stripper
- Paint thinner
- Pair distribution function
- Pair potential
- Pair production
- Paired data
- Paired metamorphic belts
- Pairing
- Pairing-based cryptography
- Pairwise independence
- Palaeochannel
- Palagonite
- Palatal
- Paleo-Tethys Ocean
- Paleocortex
- Paleocurrent
- Paleosalinity
- Paleoseismic
- Paleoseismology
- Paleosols
- Paleosurface
- Palette
- Palladium
- Palladium acetate
- Palladium chloride
- Palladium compounds
- Palladium hydride
- Palladium on carbon
- Palladium(ii) chloride
- Pallet jacks
- Palliative surgery
- Pallidotomy
- Pallor
- Palm
- Palm kernel oil
- Palm oil
- Palm print
- Palmer Drought Index
- Palmitic acid
- Palmitoleic acid
- Palmitoyl-CoA
- Palpation
- Palpitations
- Palygorskite
- Palynology
- Pan evaporation
- Pan-genome
- Panc-1
- Pancake ice
- Pancreas
- Pancreatectomy
- Pancreatic cancer
- Pancreatic disease
- Pancreatic duct
- Pancreatic islets
- Pancreatic juice
- Pancreatic lipase
- Pancreatic polypeptide
- Pancreatic pseudocyst
- Pancreatic tumor
- Pancreatitis
- Pancytopenia
- Panel
- Panel building
- Panel data
- Panhard rod
- Panitumumab
- Panniculus
- Panniculus carnosus
- Pansharpening
- Pantelides algorithm
- Panthenol
- Pantoea agglomerans
- Pantothenic acid
- Pap smear
- Pap test
- Papain
- Papain-like protease
- Papaverine
- Paper
- Paper bag
- Paper chromatography
- Paper machine
- Paper mills
- Paper prototyping
- Paper recycling
- Paper tape
- Paper towels
- Paper-based microfluidics