1. [n]  the 5th letter of the Roman alphabet
2. [n]  a fat-soluble vitamin that is essential for normal reproduction; an important antioxidant that neutralizes free radicals in the body
3. [n]  the base of the natural system of logarithms
4. [n]  the cardinal compass point that is at 90 degrees
5. [n]  a radioactive transuranic element produced by bombarding plutonium with neutrons

E
Interest earned on a bank account . . . arrangement of seeds in a sunflower . . . the shape of the Gateway Arch in St. Louis . . . are all intimately connected with the mysterious number e . In this informal and engaging history, Eli Maor portrays the curious characters and the mathematics that lie behind the number e. Designed for a reader with only a modes background in mathematics, this book brings out e`s central importance in mathematics. Illustrated.

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1. \E\ ([=e]).
   1. The fifth letter of the English alphabet.
   Note: It derives its form, name, and value from the Latin,
         the form and value being further derived from the
         Greek, into which it came from the Ph[oe]nician, and
         ultimately, probably, from the Egyptian. Its
         etymological relations are closest with the vowels i,
         a, and o, as illustrated by to fall, to fell; man, pl.
         men; drink, drank, drench; dint, dent; doom, deem;
         goose, pl. geese; beef, OF. boef, L. bos; and E. cheer,
         OF. chiere, LL. cara.
   Note: The letter e has in English several vowel sounds, the
         two principal being its long or name sound, as in eve,
         me, and the short, as in end, best. Usually at the end
         of words it is silent, but serves to indicate that the
         preceding vowel has its long sound, where otherwise it
         would be short, as in m[=a]ne, c[=a]ne, m[=e]te, which
         without the final e would be pronounced m[a^]n, c[a^]n,
         m[e^]t. After c and g, the final e indicates that these
         letters are to be pronounced as s and j; respectively,
         as in lace, rage. See Guide to Pronunciation,
         [sect][sect] 74-97.
   2. (Mus.) E is the third tone of the model diatonic scale.
      E[flat] (E flat) is a tone which is intermediate between D
      and E.
   

2. \E-\
   A Latin prefix meaning out, out of, from; also, without. See
   {Ex-}.
   

1. An extension of C++ with database types and persistent objects. E is a powerful and flexible procedural programming language. It is used in the Exodus database system.

See also GNU E.

["Persistence in the E Language: Issues and Implementation", J.E. Richardson et al, Soft Prac & Exp 19(12):1115-1150 (Dec 1989)].

2. A procedural language by Wouter van Oortmerssen with semantics similar to C. E features lists, low-level polymorphism, exception handling, quoted expressions, pattern matching and object inheritance. Amiga E is a version for the Amiga.