an arc of colored light in the sky caused by refraction of the sun's rays by rain
an illusory hope
a radioactive transuranic element produced by bombarding plutonium with neutrons
the cardinal compass point that is at 90 degrees
a fat-soluble vitamin that is essential for normal reproduction; an important antioxidant that neutralizes free radicals in the body
the 5th letter of the Roman alphabet
the base of the natural system of logarithms; approximately equal to 2.718282...