peri - plan
- perigee altitude
- perigee burn
- perigee-air-scooping spacecraft
- perigee-burn upper propulsion
- perigon angle
- period
- period of validity of a forecast
- periodic duty
- periodic law
- periodic maintenance
- periodic maintenance check
- periodically tended space station
- peripheral
- peripheral device
- peripheral field of view
- periphery-type latch
- periscope
- perishable cargo
- perishable freight
- perishables
- permafrost
- permanent aerodrome
- permanent anticyclone
- permanent echo
- permanent failure
- permanent injury
- permanent space station
- permanent virtual circuit
- permanently manned space complex
- permissible interference
- permissible load
- permit
- permitted diameter of turbine
- permitted pay load
- permitted payload
- peroxide
- perpetual frost climate
- person
- person in custody
- personal
