rice - rota
- rice combine
- rice grader
- rice husker
- rice polishing machine
- rice sheller
- rice thresher
- rice transplanter
- rich gas
- rich mixture
- riddle
- rider
- riding comfort
- riffler
- rifle
- rifled barrel
- rigging
- right angle
- right circular cone
- right cone
- right hand cutting tool
- right hand helix
- right hand rotation
- right hand rule
- right hand screw
- right hand steering
- right hand thread
- right hand tool
- right hand worm
- right triangle
- rigid airship
- rigid body
- rigid body dynamics
- rigid connection
- rigid construction
- rigid coupling
- rigid foundation
- rigid frame
- rigid joint
- rigid rotor
- rigid support
