evergreen contract
noun[C]
LAWukusalegalagreementthat willautomaticallystartagainunlessone of thepeopleorbusinessesinvolvedofficiallyendsit:
He hascommittedto beingmusicdirectorthrough the 2010-11season, after which he'll have what's called anevergreencontract,allowingyear-by-year renewals.
Compare
rolling contract