- quad cable
- quadruplet
- quadrupole field
- qualitative analysis
- quantizer
- quantum mechanics
- quantum solids
- quark
- quasi-classical
- quasi-periodic
- quasi-reversible
- quasi-variable
- quaternary
- quench
- quench voltage
- quenching action
- quenching frequency
- queue
- quick defrosting
- quick precooling
- quick-chilled
- quiet
- pyrolysed felt
- pyrometry
- pyrophoricity
- pyrophotometer
- pyrostat
- pyrotechnics
- quadruplex circuit
- quantity meter
- quantization step
- quantized vortex
- quantum condition
- quantum noise
- quartz filter
- quasi-conservative
- quasi-elastic
- quasi-equilibrium
- quasi-free
- quasi-isothermal
- quasi-periodicity
- quasi-statical
- quench frequency
- quench tank
- quick thawing
- quiescent conditions
- quill drive
- quint
- quintet
- quit
- r
- R-wire
- race condition
- raceway coil
- rack truck
- rad
- radar beam
- radar clutter
- radar detection
- radar echo
- radar pulse
- radar reflection
- radar reflector
- radar shadow
- radar volume
- radial
- radial acceleration
- radial circuit
- radial grating
- radial lead
- radial system
- radial velocity
- radiant
- radiant boiler
- radiant energy
- radiant excitation
- radiant panel
- radiant transmittance
- radiated power
- radiating curtain
- radiating element
- radiation
- radiation absorption
- radiation belt
- radiation constant
- radiation cooler
- radiation damage
- radiation damping
- radiation detection
- radiation detector
- radiation dosimeter
- radiation effect
- radiation efficiency
- radiation excitation
- radiation filter
- radiation flux
- radiation heating
- radiation intensity
- radiation lobe
- radiation preservation