Science vocabulary helps students understand concepts faster and score better in exams. Here you will find useful physical science words that all start with the letter R for clear learning.
This article explains each R word with a short meaning so anyone can learn without confusion. You will see organized sections with tables for easy reading.
The list includes physical science terms, earth science, life science, environmental science, computer science, and grade-wise vocabulary to help you improve quickly at school.
Physical Science Words That Start With R
Physical science encompasses physics and chemistry, studying matter, energy, and their interactions. Here are 15 essential physical science terms beginning with R:
| Word | Meaning |
| Radiation | Energy transmitted through waves or particles |
| Reaction | Chemical process where substances transform into new substances |
| Refraction | Bending of light as it passes through different materials |
| Resistance | Opposition to the flow of electric current |
| Reflection | Bouncing back of light or sound waves from a surface |
| Reactant | Substance that enters into a chemical reaction |
| Radioactive | Emitting energy through atomic decay |
| Reduction | Chemical reaction involving gain of electrons |
| Respiration | Process of energy release from glucose in cells |
| Resonance | Vibration at maximum amplitude at specific frequencies |
| Rotation | Spinning movement of an object around an axis |
| Redox | Chemical reaction involving transfer of electrons |
| Rarefaction | Decrease in density of a medium during wave passage |
| Refrigeration | Process of removing heat to lower temperature |
| Rectifier | Device that converts alternating current to direct current |
Earth Science Words That Start With R
Earth science explores our planet’s physical characteristics, including geology, meteorology, and oceanography. Here are 15 key earth science terms:
| Word | Meaning |
| Rock | Solid mineral material forming Earth’s crust |
| Ridge | Elongated elevation on land or ocean floor |
| River | Natural flowing watercourse moving toward ocean or lake |
| Rain | Precipitation of water droplets from clouds |
| Richter | Scale measuring earthquake magnitude |
| Relief | Elevation differences in terrain |
| Reservoir | Natural or artificial water storage area |
| Runoff | Water flowing over land surface into water bodies |
| Rift | Large crack in Earth’s crust where plates separate |
| Regolith | Layer of loose material covering bedrock |
| Rapids | Fast-flowing section of a river with turbulent water |
| Ravine | Deep narrow valley with steep sides |
| Reef | Ridge of rock or coral near water surface |
| Rhyolite | Fine-grained volcanic igneous rock |
| Radiometric | Method of dating rocks using radioactive decay |
Life Science Words That Start With R
Life science focuses on living organisms and their relationships. Here are 15 important biological terms starting with R:
| Word | Meaning |
| Reproduction | Biological process of producing offspring |
| Respiration | Process of exchanging oxygen and carbon dioxide |
| Ribosome | Cellular structure where protein synthesis occurs |
| RNA | Ribonucleic acid carrying genetic instructions |
| Root | Plant organ absorbing water and nutrients from soil |
| Receptor | Protein detecting specific molecules or stimuli |
| Recessive | Genetic trait masked by dominant allele |
| Reptile | Cold-blooded vertebrate with scaly skin |
| Regeneration | Ability to regrow lost body parts |
| Reflex | Automatic response to stimulus |
| Retina | Light-sensitive layer at back of eye |
| Ruminant | Animal that chews cud and has multiple stomachs |
| Regenerate | To grow back or restore damaged tissue |
| Respire | To breathe or undergo cellular respiration |
| Rodent | Small mammal with continuously growing incisors |
Environmental Science Words That Start With R
Environmental science examines interactions between physical, chemical, and biological components of the environment. Here are 15 relevant terms:
| Word | Meaning |
| Recycling | Converting waste materials into reusable materials |
| Renewable | Resource that naturally replenishes over time |
| Rainforest | Dense forest with high annual rainfall |
| Resources | Materials or substances used by organisms |
| Reforestation | Replanting trees in deforested areas |
| Restoration | Returning ecosystem to original condition |
| Runoff | Water pollution from surface water flow |
| Range | Geographic area where species naturally lives |
| Reservoir | Storage location for water or other substances |
| Radiation | Energy potentially harmful to living organisms |
| Reclamation | Restoring land to usable condition |
| Refuge | Protected area for endangered species |
| Remediation | Cleanup of polluted or contaminated areas |
| Riparian | Relating to riverbanks and adjacent land |
| Resilience | Ecosystem’s ability to recover from disturbance |
Computer Science Words That Start With R
Computer science involves computation, information processing, and algorithm design. Here are 15 essential computer science terms:
| Word | Meaning |
| RAM | Random Access Memory for temporary data storage |
| ROM | Read-Only Memory with permanent instructions |
| Router | Device directing data between computer networks |
| Runtime | Period when program is executing |
| Register | High-speed storage location in processor |
| Resolution | Number of pixels in digital display |
| Recursion | Function calling itself in programming |
| Repository | Central storage location for code |
| Rendering | Process of generating image from model |
| Robot | Programmable machine performing automated tasks |
| Relay | Electrically operated switch in circuits |
| Refresh | Update display or reload webpage |
| Registry | Database storing system configuration settings |
| Response | Data returned after processing request |
| Redundancy | Duplication of components for reliability |
Science Words That Start With R With Meaning
This comprehensive collection combines all scientific disciplines, providing clear definitions for learners:
| Word | Meaning |
| Radar | System using radio waves to detect objects |
| Radiant | Emitting light or heat energy |
| Radius | Distance from center to edge of circle |
| Ratio | Relationship between two quantities |
| Ray | Straight line extending from point |
| Reagent | Substance used in chemical analysis |
| Recombination | Genetic material exchange between chromosomes |
| Reflex | Involuntary response to stimulus |
| Relativity | Einstein’s theory about space and time |
| Replication | Process of copying DNA molecules |
| Resistor | Component limiting electrical current flow |
| Resultant | Combined effect of multiple forces |
| Retardation | Negative acceleration or slowing down |
| Revolve | Move in circular orbit around point |
| Rigid | Stiff and unable to bend easily |
Science Words That Start With R For Kids
These age-appropriate terms introduce young learners to scientific concepts:
| Word | Meaning |
| Rain | Water falling from clouds |
| Rainbow | Arc of colors appearing in sky |
| Rock | Hard solid material from Earth |
| Roots | Parts of plant growing underground |
| Robot | Machine that can move and work automatically |
| Recycle | Using something again instead of throwing away |
| Reptile | Cold-blooded animal with scales |
| River | Large stream of flowing water |
| Reflect | Bounce back like mirror |
| Rotate | Spin around like a top |
| Rust | Brown coating on old iron |
| Refrigerator | Machine that keeps food cold |
| Ramp | Sloped surface for moving things |
| Rocket | Vehicle that flies into space |
| Rough | Surface that is not smooth |
Science Words That Start With R 5th Grade
Fifth-grade science vocabulary builds on foundational concepts:
| Word | Meaning |
| Radiation | Energy traveling through space as waves |
| Reaction | Chemical change creating new substances |
| Refraction | Bending of light through different materials |
| Reproduction | Making offspring or new organisms |
| Respiration | Breathing process exchanging gases |
| Reflection | Bouncing of light from surfaces |
| Revolution | Complete orbit around another object |
| Renewable | Resource that can be replaced naturally |
| Resistance | Force opposing motion or flow |
| Reservoir | Place where water is collected and stored |
| Recycling | Processing used materials for reuse |
| Rainforest | Forest with very high rainfall |
| Richter | Scale measuring earthquake strength |
| Retina | Part of eye detecting light |
| Ribosome | Cell part making proteins |
Science Words That Start With R 6th Grade
Sixth-grade terms introduce more complex scientific ideas:
| Word | Meaning |
| Radioactive | Element releasing energy through decay |
| Reactant | Starting substance in chemical reaction |
| Receptor | Cell part receiving signals |
| Recessive | Trait hidden by dominant gene |
| Reduction | Chemical reaction gaining electrons |
| Reflex | Automatic body response to stimulus |
| Regeneration | Regrowing lost body parts |
| Regolith | Loose material covering bedrock |
| Relativity | Theory about space and time relationship |
| Replication | Copying process for DNA |
| Resistance | Opposition to electrical current flow |
| Resonance | Vibration at natural frequency |
| Resultant | Net force from combined forces |
| Ridge | Long narrow elevated landform |
| Rift | Large crack in Earth’s crust |
Science Words That Start With R 7th Grade
Seventh-grade vocabulary covers advanced middle school concepts:
| Word | Meaning |
| RNA | Ribonucleic acid carrying genetic information |
| Radiation | Energy transfer through electromagnetic waves |
| Radical | Atom or molecule with unpaired electron |
| Radiometric | Dating method using radioactive decay |
| Rarefaction | Region of low pressure in sound wave |
| Reactivity | Tendency of substance to undergo reaction |
| Recombination | Exchange of genetic material between chromosomes |
| Redox | Reaction involving electron transfer |
| Reforestation | Planting trees in cleared forest areas |
| Refraction | Change in wave direction entering new medium |
| Relative | Compared to something else |
| Remediation | Cleaning up environmental contamination |
| Renewable | Energy source that naturally replenishes |
| Replication | Duplication process of DNA molecules |
| Respiration | Cellular process releasing energy from glucose |
Science Words That Start With R 8th Grade
Eighth-grade terms prepare students for high school science:
| Word | Meaning |
| Radiation | Energy emission from unstable atomic nuclei |
| Radioactive | Spontaneous emission of particles or energy |
| Radioisotope | Atom with unstable nucleus emitting radiation |
| Reactant | Substance consumed during chemical reaction |
| Recessive | Allele expressed only when homozygous |
| Recombinant | DNA containing sequences from different sources |
| Rectifier | Device converting AC to DC current |
| Redox | Simultaneous oxidation and reduction reaction |
| Reduction | Chemical process involving electron gain |
| Refraction | Bending of waves through different media |
| Regeneration | Biological process of tissue regrowth |
| Relative | Measured with respect to reference point |
| Relay | Electromagnetic switch in circuits |
| Remediation | Process of environmental cleanup |
| Replication | Semi-conservative DNA copying process |
Final Thoughts
You have now explored a long list of science words starting with R, each with a clear meaning to help you understand topics better. Keep practicing these words whenever you study. Strong vocabulary always improves your confidence in science learning.
Save this list and share it with friends who want to improve their science grades. If you found it helpful, explore more guides like this to grow your knowledge. The more words you learn, the smarter and faster you solve science questions.
