- particle physics
- particle production
- particle trap
- particle-wave
- particularization
- particulate
- party line
- parylence capacitor
- Paschen series
- passive
- passive circuit
- passive filter
- passive junction
- passive network
- passive radar
- paste
- pasted plate
- patch
- patch board
- patch cord
- path difference
- path length
- path overhead
- path plotting
- path search
- pattern
- pattern generator
- paucity
- Pauli paramagnetism
- paxolin
- pawl
- peak load
- peak voltage
- peaking transformer
- peat slab
- Pedersen potentiometer
- peltier block
- Pelton wheel
- pay load
- PBX group
- PCM codec
- peak power
- peak voltmeter
- pearl lamp
- pedestal
- pedometer
- peeling
- pelletron accelerator
- pellucidity
- pencil beam
- pendulum meter
- penetrating particle
- penetrating power
- penetration coefficient
- penetration depth
- penetration probability
- penetron meson
- perchloroethylene
- percolation parameter
- percolation process
- perfect dielectric
- perfect gas
- perforated area
- performance
- performance characteristics
- performance criterion
- performance curve
- pencil
- pendulum
- pendulum motion
- penetrating ray
- pentavalent
- penumbra
- percent error
- percent modulation
- percentage humidity
- percentage saturation
- perception
- percolation
- percolation cluster
- percolation model
- perfect polarization
- perfect randomness
- perfect vacuum
- perforated surface
- perfory
- periastron
- periodic comet
- periodic defrosting
- periodic variation
- peripheral electron
- perishable commodity
- permanent field
- permanent glow
- permissible limit
- perpetual mobile
- persistence
- persistent current
- petersen coil
- petticoat