State (glossary)
(1) The values of key system element qualities or properties at a given time.
(2) A description of the current or future potential, or health of the system
Source(s)
Ackoff, R.L. 1971. Towards a System of Systems Concepts, Management Science, Vol.17 No. 11, USA.
Discussion
The first definition is a mathematical one, taken from the cybernetic world.
The second is used more practial, and is used by the System Operations or Sustainment community.