e e /ˈiː/

noun

1. The base of the natural system of logarithms; approximately equal to 2.718282...  ( e )
   the base of the natural system of logarithms; approximately equal to 2.718282...
   

 E

1. The 5th letter of the Roman alphabet  ( E )
   the 5th letter of the Roman alphabet
   
2. The cardinal compass point that is at 90 degrees  ( due east , E , eastward , east )
   the cardinal compass point that is at 90 degrees
   
3. A radioactive transuranic element produced by bombarding plutonium with neutrons  ( atomic number 99 , E , einsteinium , Es )
   a radioactive transuranic element produced by bombarding plutonium with neutrons
   
   
4. A fat-soluble vitamin that is essential for normal reproduction; an important antioxidant that neutralizes free radicals in the body  ( E , tocopherol , vitamin E )
   a fat-soluble vitamin that is essential for normal reproduction; an important antioxidant that neutralizes free radicals in the body