The Collaborative International Dictionary of English v.0.48:
Symbal \Sym"bal\, n. See Cimbal. [Obs.] [1913 Webster]The Free On-line Dictionary of Computing (30 December 2018):
SYMBAL SYMbolic ALgebra. A symbolic mathematics language with ALGOL-like syntax by Max Engeli, late 60's. Implemented for CDC 6600. ["User's Manual for the Formula Manipulation Language SYMBAL", M. Engeli, TRM-8.00, Comp Ctr UT Austin, June 1968].