Source : Webster's Revised Unabridged Dictionary (1913)

Livelong \Live"long`\, a. [For lifelong. Cf. {Lifelong}.]
   1. Whole; entire; long in passing; -- used of time, as day or
      night, in adverbial phrases, and usually with a sense of
      tediousness.

            The obscure bird Clamored the livelong night.
                                                  --Shak.

            How could she sit the livelong day, Yet never ask us
            once to play?                         --Swift.

   2. Lasting; durable. [Obs.]

            Thou hast built thyself a livelong monument.
                                                  --Milton.

Source : WordNet®

livelong
     adj : (of time) constituting the full extent or duration; "all the
           livelong day"
     n : perennial northern temperate plant with toothed leaves and
         heads of small purplish-white flowers [syn: {orpine}, {orpin},
          {live-forever}, {Sedum telephium}]