- Raman effect
- ramp function
- random access
- random fluctuation
- random noise
- random pulsing
- random scattering
- random winding
- range attenuation
- rankine cycle
- Rankine scale
- ranque effect
- rapid defrosting
- rapid hardener
- rapid precooling
- raster scanning
- rate action
- rated
- rating
- ratio adjuster
- rationalized
- ray ellipsoid
- ray path
- rayleigh law
- reactance voltage
- reactive
- reactor reflector
- reactor simulation
- real gas
- reality
- reanimation
- receiver exit
- receiving bin
- reciprocating
- reciprocating expander
- recirculating duct
- raised deck
- raman scattering
- random impurity
- random packing
- random vibration
- range extender
- ranging
- rarefaction
- rating conditions
- rayleigh cycle
- rayleigh flow
- reabsorption
- reactivation temperature
- reactive voltage
- reader
- real crystal
- receive channel
- receiver outlet
- receiver pressure
- receiving container
- receiving set
- reception
- rechilling
- reclosing
- recoil
- recoil broadening
- recoil permeability
- recombination radiation
- recondensed gas
- recondensing equipment
- recooled water
- recooler
- rectangular cavity
- rectangular fin
- rectangular outlet
- rectified vapour
- real eigenvalue
- recalescence
- received power
- receiver radiation
- receiver-drier
- receiving factor
- rechargeable
- reciprocal impedance
- reciprocal junction
- reciprocal lattice
- reciprocal relation
- reciprocity
- reclaim cycle
- reclaimed heat
- reclosing relay
- recoil effect
- recoil reaction
- recoil state
- recombination spectra
- recommended temperature
- reconcentration
- reconditioned air
- recool
- recooling
- recording
- recording ink
- recording instrument
- recovery