- roverOne who roves: a person or animal that travels around, especially over a wide area, without a fixed destination; a nomad, a roamer, a wanderer.
- rotaryCapable of rotation.
- rotaA schedule that allocates some task, responsibility or (rarely) privilege between a set of people according to a (possibly periodic) calendar.
- rotavirusAny of a group of wheel-shaped viruses, of the genus Rotavirus, that causes gastroenteritis and diarrhea in children and animals.
- rotundHaving a round, spherical or curved shape; circular; orbicular.
- rotiferAny of many minute aquatic multicellular organisms, of the phylum Rotifera, that have a ring of cilia resembling a wheel.
- rotoloA kind of roll.
- birotateTwo-wheeled.
- rotalOf or relating to wheels.
- rotiformHaving the shape of a wheel.
- rowelA small spiked wheel on the end of a spur of certain types.