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

Embedded Mode

    A term used by COCOMO to describe a project
   development that is characterised by tight, inflexible
   constraints and interface requirements.  The product must
   operate within (is embedded in) a strongly coupled complex of
   hardware, software, regulations and operational procedures.
   An embedded mode project will require a great deal of
   innovation.  An example would be a real-time system with
   timing constraints and customised hardware.

   (1996-05-29)