unless: used in law after decree, order, etc. to indicate that it shall take permanent effect at a specified time unless cause is shown why it should not, or unless it is changed by further proceedings
Origin of nisiClassical Latin from ne-, not (see no) + si, if (see so)
Taking effect at a specified date only if no cause is shown for modification during the interim: a decree nisi.
Origin of nisiLatin unless ; see ne in Indo-European roots.
nisi - Legal Definition
Of an ex parte decision or ruling, that it is valid unless opposed by the adverse party.