Source : Webster's Revised Unabridged Dictionary (1913)

Sigla \Sig"la\, n. pl. [L.]
   The signs, abbreviations, letters, or characters standing for
   words, shorthand, etc., in ancient manuscripts, or on coins,
   medals, etc. --W. Savage.

Source : Free On-Line Dictionary of Computing

SIGLA
     
         SIGma LAnguage.  A language for industrial robots
        from {Olivetti}.
     
        ["SIGLA: The Olivetti Sigma Robot Programming Language",
        M. Salmon, Proc 8th Intl Symp on Industrial Robots, 1978,
        pp. 358-363].