- R ... Rabbit Hole
- Rabbit Hole ... Racette, Patricia
- Racette, Patricia Lynn ... Radburn
- Radcliffe ... radiation poisoning
- radiation pressure ... Radio Music Society
- Radio Nacional Española ... Radium Hospital
- radium-224 ... Rāfiḍah
- Rafinesque, Constantine Samuel ... Rahad, Nahr Al-
- Rahal Ġdid ... Raimond de Saint-Gilles
- Raimondi Stone ... Rainwater, Leo James
- Rainy Day in New York, A ... Rajasthan Royals
- Rajasthan Steppe ... Ralaimongo, Jean
- Ralak pok khsac ... Rāmacandra
- Rāmacarita ... Ramcharitmanas
- Ramdaspur ... Ramon Berenguer the Holy
- Ramon Berenguer the Towhead ... Ramsey, Isabella May
- Ramsey, Michael, Baron Ramsey of Canterbury ... Randolph, John
- Randolph, Marc ... Rangoon, University of
- Rangpur ... Raoul de Houdan
- Raoul de Houdenc ... Rappite
- Rappler ... Rashīdīyeh
- Rashidun ... rat snake
- Rat, The ... Rational Studies
- rational systems perspective ... Raumo
- Raup, Hugh M. ... Rawlins, John A.
- Rawlins, Thomas ... Raynald of Châtillon
- Raynaud phenomenon ... Rdio
- rdo-rje ... Reader, The
- reader-response criticism ... Real Valladolid
- Real Villa de San Felipe de Austria ... Rebay, Hilla
- rebbe ... recessional moraine
- recessive trait ... Recollections of My Youth
- Recollections of the Table-Talk of Samuel Rogers ... rectification
- Rectification Campaign ... red blindness
- red blood cell ... Red Hook Summer
- red horned poppy ... Red Rose Speedway
- Red Roses for Me ... red-breasted nuthatch
- red-breasted stilt ... Redfield, Robert
- Redfield, William C. ... reduction class
- reduction division ... Reeds Peak
- Reeds, Plain of ... Reflections in a Golden Eye
- Reflections of a Free Black Man ... Reformverein
- refracting telescope ... Regent’s Park
- regenta, La ... registration
- registration ... Regulus goodfellowi
- Regulus ignicapillus ... Reid, Andrew Walter
- Reid, Andy ... Reinmar the Elder
- Reinmar von Hagenau ... relational database
- relational file structure ... relief map
- Relief of Poor Widows with Small Children, Society for the ... Reliquary of the Holy Thorn
- Reliques of Ancient English Poetry ... Remington Steele
- Remington Typewriter ... renal sinus
- renal system ... renminbi
- Renn, Ludwig ... repeater jamming
- Repeating Island, The ... Representatives, House of
- Representatives, House of ... Republican Forces of Ivory Coast
- Republican Guard ... Reşad, Mehmed
- Resagi, Mount ... residence time
- residence time ... resonance
- resonance ... Ressa, Maria Angelita
- Resserella ... resuscitation
- Reszke, Jean de ... Retiro Park
- Retiro, El ... Returned Services League of Australia
- returning boomerang ... revenue tariff
- Revenue, Board of ... Revolt Against Dualism, The
- Revolt in Aspromonte ... rex sacrorum
- Rex, Al ... RFSTE
- RFSTN ... rheiform
- Rheiformes ... Rhinella marina
- rhinestone ... Rho-GAM
- Rhoads, Randy ... rhombi
- rhombic sulfur ... Rhys, Lord
- Rhys, Siôn Dafydd ... Ribera, F. de
- Ribera, Giuseppe de ... Rice, Henry Grantland
- Rice, Irene ... Richard, Cliff
- Richard, Maurice ... Richie, Lionel Brockman, Jr.
- Richier, Germaine ... Rickettsia prowazekii
- Rickettsia rickettsii ... ridged green snake
- Ridgeley, Andrew ... Riffi
- Riffian ... right-angled triangle
- right-eyed flounder ... Rikken Dōshi-kai
- Rikken Dōshikai ... Rinaldo Rinaldini, der Rauberhauptmann
- rinceau ... rings
- Ringsaker ... Río Madre de Dios
- Río Magdalena ... ripgut grass
- Riphean sequence ... rising sun
- Rising Sun ... Ritter von Kahr, Gustav
- Ritter, Carl ... River, The
- River, The ... Riyadus-Salikhin
- riyal ... road race
- Road River Group ... Robbia, Andrea della
- Robbia, Giovanni della ... Robert the Wise
- Robert Wood Johnson Foundation ... Robertson, Oscar Palmer
- Robertson, Pat ... Robinson, Joan
- Robinson, Joan Violet ... Rocard, Michel Louis Leon
- Rocard, Yves-André ... Rock Cornish
- rock cranberry ... rock-knob landscape
- rockabilly ... Rocky
- Rocky Aur Rani Kii Prem Kahaani ... Rodino, Pellegrino Wallace, Jr.
- Rodino, Peter ... Roentgen, David
- Roentgen, Wilhelm Conrad ... Rogue’s Rest
- Rogun Dam ... Roland von Berlin, Der
- Roland, Der ... Rollinia pulchrinervis
- Rollins Band, the ... Roman Ladies’ Dog
- Roman law ... Romanian hamster
- Romanian language ... Romeo + Juliet
- Romeo and Juliet ... Ronan, Saoirse Una
- Roncador Mountains ... Room for One More
- Room for Squares ... rootkit
- rootlet ... Rosary College
- Rosary of the Blessed Virgin ... Rose, Peter Edward
- Rose, Ralph Waldo ... Rosenstock, Samuel
- Rosenstock-Huessy, Eugen ... Ross, Henry Stewart, Earl of
- Ross, Herbert ... Rosten, Leo Calvin
- Rostislav ... rotational symmetry
- rotational time ... Rotoialum
- rotoinversion axis ... Rouher, Eugène
- rouille ... Roussy, Anne-Louis Girodet de
- Roustchouk ... Roxana
- Roxana ... Royal College of Chaplains
- Royal College of Physicians of London ... Royal North Devon Club
- Royal Norwegian Society of Learning ... Rozanov, Vasily Vasilyevich
- Rozanova, Olga Vladimirovna ... Ruanda
- Ruanda ... rubrospinal tract
- Rubruquis, Wilhelmus ... Rudnyj
- Rūdnyy ... Rufus, Rutilius
- Rufus, Servius Sulpicius ... Rukhnama
- Ruki River ... Rumelia
- Rumelihisarı ... Rundstedt, Karl Rudolf Gerd von
- Rundu ... Rupp, Adolph
- Rupp, Adolph Frederick ... Ruskyi
- Ruslan and Ludmila ... Russian Baptist Union
- Russian Baroque ... Rustaveli, Shota
- Rustavi ... Rutledge, John
- Rutledge, Wiley B., Jr. ... Ryan, Rex
- Ryan, Robert ... Ryurik
- Ryzhkov, Nikolai ... Rzhev
