Source : WordNet®

epsilon
     n : the 5th letter of the Greek alphabet

Source : Free On-Line Dictionary of Computing

epsilon
     
        1.  The fifth letter of the Greek alphabet.
     
        2.  (From the Hungarian mathematician {Paul
        Erdos}) A very small, insignificant, or negligible quantity of
        something.
     
        The use of epsilon is from the {epsilon-delta method} of
        {proof} in {differential calculus}.
     
        (2001-07-06)

EPSILON
     
         A {macro} language with high level features
        including strings and lists, developed by A.P. Ershov at
        Novosibirsk in 1967.  EPSILON was used to implement {ALGOL 68}
        on the {M-220}.
     
        ["Application of the Machine-Oriented Language Epsilon to
        Software Development", I.V. Pottosin et al, in Machine
        Oriented Higher Level Languages, W. van der Poel, N-H 1974,
        pp. 417-434].
     
        [{Jargon File}]
     
        (1995-05-10)