This list includes 20 Prefixes that start with R, from “rachi-” to “rubro-“. They are well-attested across Latin, Greek, Old English, and modern scientific coinages, chosen for frequency and usefulness in word-building and etymology.

Prefixes that start with R are short word elements you attach to bases to change or refine meaning. Many come from Latin or Greek and appear across medical, scientific, and everyday vocabulary. For example, “rubro-” traces to Latin ruber meaning “red,” seen in color terms and historical rubrics.

Below you’ll find the table with Prefix, Origin, Meaning, Example words, Notes, Sources.

Prefix: The actual prefix string you can add to words; you use this to spot and build related terms.

Origin: The root language or source, so you understand historical meaning and common word relatives.

Meaning: A concise definition (three to seven words) showing how the prefix changes a base word.

Example words: Two to four clear examples that show common real-world uses you can recognize or emulate.

Notes: Short usage tips, register (formal/informal), or fields where the prefix is common, helping you apply it correctly.

Sources: Where the entry is verified, listed so you can follow up for etymology or further reading.

Prefixes that start with R

PrefixOriginMeaningExample words
re-Latinagain, backrewrite, return, react
retro-Latinbackward, pastretrograde, retroactive, retrofit
radio-Latinradiation, rays; radio waveradioactive, radiology, radioisotope
recti-Latinstraight, rightrectilinear, rectitude, rectify
reno-Latinkidneyrenal, renography, renohepatic
rete-Latinnet, networkreticulum, reticulate, rete mirabile
rhizo-Greekrootrhizome, rhizobia, rhizoid
rhodo-Greekrose, redrhododendron, rhodopsin, Rhodophyta
rhino-Greeknoserhinoplasty, rhinovirus, rhinoceros
rhabdo-Greekrod-shapedrhabdomyolysis, rhabdovirus, rhabdite
rhombo-Greekdiamond-shaped, slantedrhomboid, rhombic
rheo-Greekflowrheology, rheostat, rheometer
rhytid-Greekwrinklerhytidectomy, rhytidoplasty
rachi-Greekspine, backbonerachis, rachitic, rachipagus
rhapso-Greeksew together, stitch; lyrical patchworkrhapsody, rhapsodize, rhapsodic
rubro-Latinredrubrospinal, rubrothalamic, rubrocaudal
rhamno-Greekbuckthorn (plant); used for rhamnoserhamnose, Rhamnaceae, rhamnolipid
retin(o)-Latinretina; related to vision or vitamin Aretinol, retinopathy, retinitis
raph(e)-Greekseam, sutureurogenital raphe, palatal raphe, raphe nucleus
roentgeno-German (eponym)X‑ray (Roentgen) imagingroentgenogram, roentgenography

Descriptions

re-
The most productive English prefix meaning “again” or “back”; appears across registers and assimilates before consonants (re‑/red‑/rev‑).
retro-
Common in everyday and technical use to signal “backward” or “looking to the past”; widely used in cultural and scientific terms.
radio-
From Latin radius “ray”; highly productive in science and media (radiology, radio); often signals radiation or broadcasting.
recti-
From rectus “straight/right”; appears in formal and technical vocabulary to indicate straightness or correctness.
reno-
Medical/anatomical combining form for kidney-related terms; common in clinical contexts.
rete-
Classical anatomical/biological form meaning “net”; used in formal scientific contexts.
rhizo-
Botanical and microbiological combining form meaning “root”; common in scientific vocabulary.
rhodo-
Denotes red/rose color in taxonomy and biochemistry; appears frequently in biology.
rhino-
Very familiar medical/biological prefix for “nose”; also appears in common words like rhinoceros.
rhabdo-
Technical biomedical form meaning “rod-shaped”; used in pathology and virology.
rhombo-
Geometric combining form from Greek rhombos; used in math, anatomy, and descriptive geometry.
rheo-
Scientific/engineering prefix related to flow and current; common in physics and material science.
rhytid-
Surgical/cosmetic combining form for “wrinkle”; used in medical and cosmetic contexts.
rachi-
Anatomical combining form (often rachi(o)-) relating to the spine; standard in medical terminology.
rhapso-
Originally “sewn together” (texts/songs); now literary and musical, also appears in historical technical senses.
rubro-
Anatomical/biological combining form meaning “red”; used in neuroanatomy (red nucleus) and technical terms.
rhamno-
Botanical/chemical combining form used in plant names and carbohydrate chemistry; specialized register.
retin(o)-
Medical/biological combining form linked to the retina or vitamin A derivatives; common in ophthalmology and biochemistry.
raph(e)-
Anatomical combining form referring to a seam or ridge; used in anatomy and histology, mildly technical.
roentgeno-
Eponymous technical prefix (from Röntgen) used historically in radiology contexts; less common in everyday speech.
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