- Rescue effect
- Rescue robot
- Research reactors
- Resection
- Resection margin
- Reservation price
- Reserved words
- Reservoir computing
- Reservoir engineering
- Reservoir modeling
- Reservoir sampling
- Reservoir simulation
- Reservoirs
- Residence time
- Residential care
- Residential gateway
- Residual
- Residual entropy
- Residual gas analyzer
- Residual neural network
- Residual strength
- Residual stress
- Residual sum of squares
- Residuals
- Residue
- Residue theorem
- Residuum
- Resilience
- Resilience engineering
- Resin
- Resin acids
- Resin casting
- Resistance curve
- Resistance thermometers
- Resistance wire
- Resistant starch
- Resistin
- Resistive pulse sensing
- Resistivity
- Resistome
- Resistor
- Resolvers
- Resonance
- Resonance Raman spectroscopy
- Resonance ionization
- Resonant column test
- Resonant converter
- Resonant inductive coupling
- Resonant inelastic x-ray scattering
- Resonant interaction
- Resonant inverter
- Resonant tunneling diode
- Resonant ultrasound spectroscopy
- Resonant-tunneling diode
- Resonators
- Resorcinarene
- Resorcinol-formaldehyde
- Resource allocation
- Resource consumption
- Resource contention
- Resource depletion
- Resource efficiency
- Resource intensity
- Resource management
- Resource productivity
- Respiration rate
- Respiratory acidosis
- Respiratory alkalosis
- Respiratory arrest
- Respiratory burst
- Respiratory depression
- Respiratory droplets
- Respiratory epithelium
- Respiratory exchange ratio
- Respiratory failure
- Respiratory quotient
- Respiratory rate
- Respiratory sounds
- Respiratory system
- Respiratory tract
- Respiratory tract infections
- Respirometry
- Response amplitude operator
- Response bias
- Response factor
- 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