rela - ring
- relative sunspot number
- relativistic astrophysics
- relativistic cosmology
- relativistic disks
- relativistic effects
- relativistic electrons
- relativistic fluid dynamics
- relativistic gas
- relativistic mechanics
- relativistic particles
- relativistic plasmas
- relativistic stars
- relativistic velocity
- relativity
- relaxation time
- remote control systems
- remote sensing
- research
- reseaux
