- resolver
- resolving cell
- resonance absorption
- resonance fluorescence
- resonance radiation
- resonance ratio
- resonance region
- resonance transfer
- resonant diaphragm
- resonant helix
- resonant window
- resonator wavemeter
- resorb
- resorption
- respiratory intensity
- respond
- response
- response time
- responsive behaviour
- rest potential
- restrictor valve
- restriking voltage
- reststrahlen
- resultant
- retarding action
- resistance head
- resistance voltage
- resistive load
- resistive unbalance
- resonance
- resonance reaction
- resonance transformer
- resonant capacitor
- resonant iris
- resonant resistance
- resonoscope
- resorption refrigeration
- response delay
- restored state
- restricted
- restriction
- resublimation
- resurfacing
- retained image
- retarded field
- retarded potentials
- retarder
- retentivity
- retrace time
- return air
- return conduit
- return pump
- reverberation
- reverberant field
- reverberation time
- reverse power
- reversible permeability
- rheostat
- ribbon cable
- ribbon conductor
- ribbon microphone
- Rietveld refinement
- right
- rigid body
- rigid insulant
- rigid Styrofoam
- rigid urethane
- rigidity
- reverse-reaction
- reversible path
- revolve
- rewind
- rheopectic fluid
- rhombohedral
- rib
- ribbed cooler
- rich vapour
- ring system
- ringing current
- ringing tone
- ripple
- rise time
- rising main
- rising time
- rethawing
- retop icing
- return channel
- return coefficient
- return difference
- return flow
- return loss
- return pipe
- return wire
- reusable heat
- reverberation room
- reverse key
- reversed
- reversible expansion
- reversing motor
- RF shielding