- radial flow
- radiant heating
- radiant power
- radiant section
- radiated pyrite
- radiated structure
- radiating gill
- radiating guide
- radiation dose
- radiation hardening
- radiation logging
- radiation rate
- radiator
- radical polymerization
- radical reaction
- radical sign
- radical valence
- radical weight
- radio-active
- radio-colloid
- radio-element
- radio-lead
- radio-location
- radioactive change
- radioactive constant
- radioactive earth
- radioactive family
- radioactive isotope
- radioactive log
- radioactive rays
- radioactive rock
- radioactive substance
- radioactive transformation
- radioactive waste
- radiocarbon
- radiochemistry
- radioidine
- radiolarian rock
- radiolitic structure
- radiometry
- radiomimetic
- radiopaque
- radium
- radium salt
- radon
- rafaelite
- rag line
- ragged
- raimondite
- rain chart
- rain print
- rain scatter
- radium ore
- radostrontium
- raffinate
- rag bolt
- ragstone
- railroad oil
- rain gage
- raised beach
- Ramsbottom method
- random arrangement
- rate
- rate constant
- rated current
- rated pressure
- ratholing
- ravine
- ravine stream
- raw
- raw copper
- raw distillate
- raw ore
- raw salt
- raw stock
- rawhide
- rayon
- re-boiler
- re-carburization
- re-crystallization
- reabsorbed crystal
- reactant
- reaction chain
- reaction column
- reaction mass
- reaction medium
- reaction stress
- reaction test
- reaction velocity
- reaction zone
- reactor
- rebate
- reboiler
- raindrop impression
- raindrop imprint
- raised coast
- raised face
- raising leg
- rake
- ramdohrite