To set up in business; to place advantageously in a fixed condition; -- used reflexively; as, he established himself in a place; the enemy established themselves in the citadel.
To originate and secure the permanent existence of; to found; to institute; to create and regulate; -- said of a colony, a state, or other institutions.
establish the validity of something, as by an example, explanation or experiment; "The experiment demonstrated the instability of the compound"; "The mathematician showed the validity of the conjecture"
To secure public recognition in favor of; to prove and cause to be accepted as true; as, to establish a fact, usage, principle, opinion, doctrine, etc.
(est, not est)"Establishment" is field survival for at least 2 years. "Not est" or "Not established" does not necessarily mean that the agent cannot be established as this often requires many releases over several years (Harris, P. 1996).