- Pent-roof combustion chamber
- Penta-graphene
- Pentabde
- Pentacene
- Pentachlorobenzene
- Pentachloroethane
- Pentachlorophenol
- Pentadecanoic acid
- Pentadiene
- Pentaerythritol
- Pentaerythritol tetraacrylate
- Pentaerythritol tetranitrate
- Pentafluoropropane
- Pentagon
- Pentagonal bipyramid
- Pentamer
- Pentamidine
- Pentane
- Pentavalent antimonial
- Pentene
- Pentium
- Pentium 4
- Pentlandite
- Pentosan
- Pentose phosphate pathway
- Pentoses
- Pentoxifylline
- Pentraxins
- Pentyl
- Pepper
- Peppermint
- Pepsin
- Pepstatin
- Peptic ulcer disease
- Peptic ulcers
- Peptide amphiphiles
- Peptide bonds
- Peptide hormones
- Peptide mass fingerprinting
- Peptide synthesis
- Peptides
- Peptidoglycan
- Peptization
- Pepto-Bismol
- Peptoids
- Per capita
- Per unit mass
- Per- and polyfluoroalkyl substances
- Per-unit system
- Peracetic acid
- Peralkaline
- Peramivir
- Perceived Stress Scale
- Perceived performance
- Percentage
- Percentile
- Percentile rank
- Perception
- Perceptrons
- Perceptual evaluation of speech quality
- Perceptual hashing
- Perchlorate
- Perchloric acid
- Percolation
- Percolation test
- Percolation theory
- Percolation threshold
- Percoll
- Percussion caps
- Percutaneous
- Percutaneous aortic valve replacement
- Percutaneous nephrolithotomy
- Perdido
- Perennial rivers
- Perennial stream
- Perfect conductor
- Perfect crystal
- Perfect field
- Perfect gas
- Perfect graph
- Perfect information
- Perfect matching
- Perfect mirror
- Perfect mixing
- Perfect thermal contact
- Perfluorinated compounds
- Perfluoroalkyl carboxylic acids
- Perfluorobutanesulfonic acid
- Perfluorodecanoic acid
- Perfluorohexane
- Perfluorohexanesulfonic acid
- Perfluorohexanoic acid
- Perfluorooctane
- Perfluorooctanesulfonic acid
- Perfluorooctanoic acid
- Perfluoropolyether
- Perfluorosulfonic acids
- Perforated
- Perforated metal
- Perforating
- Perforation
- Perforin
- Performance gap
- Performance improvement
- Performance indicator
- Performance per watt
- Performance prediction
- Performance rating
- Performance status
- Performance-based logistics
- Performic acid
- Perfume
- Perfusion
- Perfusion CT
- Perfusion scanning
- Perfusionists
- Peri-implantitis
- Periaqueductal gray
- Pericardial
- Pericardial effusion
- Pericardial fluid
- Pericardiocentesis
- Pericarditis
- Perichondrium
- Periclase
- Pericyclic reactions
- Peridinin
- Peridotite
- Peridynamics
- Perillyl alcohol
- Perilymph
- Perimeter
- Perimeter security
- Perimetry
- Perimysium
- Perinatal mortality
- Perineural invasion
- Perineurium
- Period
- Period lattice
- Period-doubling bifurcation
- Periodate
- Periodic acid
- Periodic boundary conditions
- Periodic functions
- Periodic orbit
- Periodic sequence
- Periodic table
- Periodic trends
- Periodontal disease