China 
Africa 
- Response rate
- Response spectrum
- Responsibility assignment matrix
- Responsible mining
- Responsive web design
- Responsiveness
- Responsivity
- Rest frame
- Rest mass
- Restenosis
- Resting metabolic rate
- Resting potential
- Resting state fMRI
- Restite
- Restless legs syndrome
- Restoration
- Restoring force
- Restricted maximum likelihood
- Restriction enzymes
- Restriction fragment
- Restriction sites
- Restrictive lung disease
- Result set
- Resultant
- Resultant force
- Resummation
- Resuscitation
- Resveratrol
- Retaining rings
- Retaining walls
- Retarded time
- Retarders
- Rete algorithm
- Retene
- Retention aid
- Retention basin
- Retention factor
- Retention rate
- Reticle
- Reticular cells
- Reticular fibers
- Reticular formation
- Reticulin
- Reticulocyte
- Retiming
- Retina
- Retinaculum
- Retinal degeneration
- Retinal detachment
- Retinal ganglion cells
- Retinal haemorrhage
- Retinal hemorrhage
- Retinal implant
- Retinal vasculitis
- Retinitis
- Retinitis pigmentosa
- Retinoblastoma
- Retinoblastoma protein
- Retinohypothalamic tract
- Retinoic acid
- Retinoic acid receptor
- Retinol binding protein
- Retinol-binding protein
- Retinopathy
- Retinopathy of prematurity
- Retinotopic
- Retinyl palmitate
- Retorts
- Retractors
- Retransmission
- Retreat mining
- Retrieval
- Retrieve
- Retrogradation
- Retrograde condensation
- Retrograde ejaculation
- Retroperitoneal
- Retroperitoneal lymph node dissection
- Retroreflectors
- Retrospective think aloud
- Retrotransposons
- Retroviruses
- Rett syndrome
- Return loss
- Return period
- Return statement
- Return type
- Return value
- Returns to scale
- Retweet
- Reuptake
- Reuptake inhibitor
- Reusability
- Reusable
- Reusable launch vehicle
- Reusable packaging
- Reusable spacecraft
- Revascularization
- Revealed preference
- Revegetation
- Reverberation room
- Reversal potential
- Reverse Monte Carlo
- Reverse cholesterol transport
- Reverse electrodialysis
- Reverse engineering
- Reverse genetics
- Reverse leakage current
- Reverse logistics
- Reverse osmosis
- Reverse osmosis plant
- Reverse proxy
- Reverse short-channel effect
- Reverse transcriptase
- Reverse transcription loop-mediated isothermal amplification
- Reverse transcription polymerase chain reaction
- Reverse-transcriptase inhibitors
- Reversed-phase chromatography
- Reversible
- Reversible computing
- Reversible hydrogen electrode
- Reversible process
- Reversible reaction
- Reversible-deactivation radical polymerization
- Reversing valve
- Revetment
- Review
- Revised simplex method
- Revolute joint
- Revolving door
- Reward system
- Rework
- Rewriting
- Reynolds analogy
- Reynolds decomposition
- Reynolds equation
- Reynolds number
- Reynolds stress
- Rhabdomyolysis
- Rhabdomyosarcoma
- Rhamnose
- Rhenium
- Rhenium hexafluoride
- Rheology
- Rheometers
- Rheometry
- Rheopectic
- Rheopecty
- Rheotaxis
- Rhetorical Structure Theory