Dictionaries, Thesauruses, Pictures, and Press Releases
- ratfish
- Rathke, Martin Heinrich
- Ratitae
- rattlesnakes
- Raukumara
- Raulin, Jules
- Raunkiaer's life-form classification
- Raunkiaers life-form classification
- Rauwolf, Leonhard
- Ravenala
- ravens
- ravine wind
- ravine wind
- ravinement surface
- Rawtheyan
- Ray's bream
- Ray, Prafulla Chandra
- ray-finned fish
- Rayet, Georges Antoine Pons
- Rayleigh wave