- Richardson vole
- red_backed mouse
- redback vole
- rotatory joint
- ranker
- round the clock
- reactive
- ream (of paper)
- ream
- roman mile
- reinvent the wheel
- reassail
- rough textured
- roseau
- rendezvous
- recco
- recce
- roared
- respondent's side
- respondent
- reporter gene
- reportedly
- rock the boat
- rock wool
- richard i
- robert wilhelm bunsen
- red nucleus
- red degeneration
- reassuring
- roadworthiness
- roly poly pudding
- rolodex
- ritonavir
- reverse video
- regularly irregular pulse
- regulate
- regulated
- rapid growers
- rapid city
- rapid mechanical filter
- richard august carl emil erlenmeyer
- recessive
- recessive allele
- recessive mendelian factor
- recessive defect
- Rotary International
- Rotary Club
- revisal
- rescript
- rattle the chain