双壳目：粘体亚门(Myxozoa)粘孢子纲(Myxosporea)中的寄生性原虫目，其孢子具二壳，故名；含三个亚目：双极虫亚目(Bipolarina)、阔孢亚目(Eurysporina)和扁孢亚目(Platysporina)- roll
- roller
- Roller's nucleus
- Rolleston's rule
- Rollet's stroma
- Rollier's radiation, treatment
- romanoscope
- Romanovsky's(Romanowsky's) stain (meth-od)
- rombergism
- Romberg's disease (trophoneurosis), sign, spasm,station
- Romilar
- Rommelaere's sign
- Rondomycin
- rongeur
- Roniacol
- ronidazole
- ronnel
- roof
- room
- rooming-in
- root
- rootlet
- R.O.P.
- ropizine
- Rorschach test