WordNet (r) 3.0 (2006):

sine die
    adv 1: without a date fixed (as of an adjournment)

Bouvier's Law Dictionary, Revised 6th Ed (1856):

SINE DIE. Without day. A judgment for a defendant in many cases is quod eat
sine die, that he may go without day. While the cause is pending and
undetermined, it may be continued from term to term by dies datus. (q.v.)
See Huxley's Judgments & Rastal's Entries, passim; Co. Litt. 362b & 363a.
When the court or other body rise at the end of a session or term they
adjourn sine die.