Source : Webster's Revised Unabridged Dictionary (1913)

Perpetual \Per*pet"u*al\, a. [OE. perpetuel, F. perp['e]tuel,
   fr. L. perpetualis, fr. perpetuus continuing throughout,
   continuous, fr. perpes, -etis, lasting throughout.]
   Neverceasing; continuing forever or for an unlimited time;
   unfailing; everlasting; continuous.

         Unto the kingdom of perpetual night.     --Shak.

         Perpetual feast of nectared sweets.      --Milton.

   {Circle of perpetual apparition}, or {occultation}. See under
      {Circle}.

   {Perpetual calendar}, a calendar so devised that it may be
      adjusted for any month or year.

   {Perpetual curacy} (Ch. of Eng.), a curacy in which all the
      tithes are appropriated, and no vicarage is endowed.
      --Blackstone.

   {Perpetual motion}. See under {Motion}.

   {Perpetual screw}. See {Endless screw}, under {Screw}.

   Syn: Continual; unceasing; endless; everlasting; incessant;
        constant; eternal. See {Constant}.

Source : WordNet®

perpetual
     adj 1: continuing forever or indefinitely; "the ageless themes of
            love and revenge"; "eternal truths"; "life
            everlasting"; "hell's perpetual fires"; "the unending
            bliss of heaven" [syn: {ageless}, {eternal}, {everlasting},
             {unending}, {unceasing}]
     2: uninterrupted in time and indefinitely long continuing; "the
        ceaseless thunder of surf"; "in constant pain"; "night and
        day we live with the incessant noise of the city"; "the
        never-ending search for happiness"; "the perpetual
        struggle to maintain standards in a democracy"; "man's
        unceasing warfare with drought and isolation";
        "unremitting demands of hunger" [syn: {ceaseless}, {constant},
         {incessant}, {never-ending}, {unceasing}, {unremitting}]
     3: occurring so frequently as to seem ceaseless or
        uninterrupted; "a child's incessant questions"; "your
        perpetual (or continual) complaints" [syn: {incessant}, {endless}]