Source : Free On-Line Dictionary of Computing

MODSIM
     
         A general-purpose, modular, block-structured
        language from {CACI}, which provides support for
        {object-oriented programming} and {discrete event simulation}.
        It is intended for building large process-based discrete event
        simulation models through modular and object-oriented
        mechanisms similar to those of {Modula-2}.
     
        MODSIM is descended from {Modula-2} and {Simula}.  It supports
        {multiple inheritance}, {template}s, {reference type}s,
        {polymorphism}, and {process-oriented simulation} with
        synchronous and asynchronous activities using explicit
        simulation time.
     
        See also {MODSIM II}, {USAModSim}.
     
        (1994-11-11)