radi - rain
- radial acceleration
- radial inflow
- radial Reynolds number
- radial spectrum
- radial symmetry
- radial velocity
- radial wavenumber
- radial wind
- radian
- radiance
- radiant density
- radiant emittance
- radiant energy
- radiant energy density
- radiant exitance
- radiant exposure
- radiant flux
- radiant flux density
- radiant heat
- radiant intensity
- radiant point
- radiant power
- radiant-energy thermometer
- radiate
- radiation
- radiation balance
- radiation balance meter
- radiation belt
- radiation boundary condition
- radiation budget
- radiation chart
- radiation climate
- radiation cooling
- radiation damping
- radiation equilibrium
- radiation feedback
- radiation filter
- radiation flux divergence meter
- radiation fog
- radiation frost
