“+ adjective
Etymology: International Scientific Vocabulary meta- + stable
: marked by only a slight margin of stability — used especially in chemistry and physics
a supercooled liquid is metastable
many of the processes in the atmosphere are … metastable : a slight action may initiate a very large-scale process — Roger Revelle
life is fleeting, metastable , a thing of delicate equilibrium of easily decomposed compounds — C.C.Furnas