The Collaborative International Dictionary of English v.0.48:

gamma \gam"ma\ (g[a^]m"m[.a]), n.
   The third letter ([Gamma], [gamma] = Eng. G) of the Greek
   alphabet.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gamma
    n 1: the 3rd letter of the Greek alphabet
    2: a unit of magnetic field strength equal to one-hundred-
       thousandth of an oersted
    3: Portuguese navigator who led an expedition around the Cape of
       Good Hope in 1497; he sighted and named Natal on Christmas
       Day before crossing the Indian Ocean (1469-1524) [syn: da
       Gamma, Vasco da Gamma, Gamma]

The Free On-line Dictionary of Computing (30 December 2018):

GAMMA

    1. A language for matrices and generation of
   mathematical programming reports.

   ["GAMMA 3.3 for MPS/MPSX, IBM System:/360", Bonnor & Moore
   Assocs (Mar 1975)].

   2. A high-level parallel language.

   [Research Directions in High-Level Parallel Languages,
   LeMetayer ed, Springer 1992].

   (1994-11-29)