(In a hypothetical scenario) the notional substance which would be all that remains after the consumption of all matter on earth by self-replicating nanobots; the scenario positing such a process and result.
Origin
1980s.
Definition of grey goo in US English:
grey goo
(USgray goo)
noun
(In a hypothetical scenario) the notional substance which would be all that remains after the consumption of all matter on earth by self-replicating nanobots; the scenario positing such a process and result.