race (human)
Race is a biological term that is used to describe groups of animals (including humans) or sometimes plants. It was once believed that there were several races of humans, but modern genetics has shown this not to be the case. In the meantime, race and racist have become entrenched in common usage, no longer having any scientific validity, but being used ambiguously to suggest a range of features, from nationality and skin colour to religion and parentage. Although race remains a valid term in biology, it is an invalid term with which to describe human variation. Racist is similarly ambiguous, its meaning being more accurately embraced by terms such as xenophobe or bigot.
rainfall, rainwater, runoff, stormwater
rainfall: the amount (usually measured in millimetres) of rain that falls in a given period and area
rainwater: water that has fallen as rain
runoff: rainwater that is not absorbed into soil but flows on the surface as streams
stormwater: water that produces a sudden, large runoff after a storm
rainwater
recyclable
regime, regimen
Interchangeable terms from the same Latin root meaning a plan, system or routine. Regime can also relate to government; regimen is more common in health and medical writing.
regimen
See regime, regimen