Source : Webster's Revised Unabridged Dictionary (1913)

Long \Long\, a. [Compar. {Longer}; superl. {Longest}.] [AS.
   long, lang; akin to OS, OFries., D., & G. lang, Icel. langr,
   Sw. l[*a]ng, Dan. lang, Goth. laggs, L. longus. [root]125.
   Cf. {Length}, {Ling} a fish, {Linger}, {Lunge}, {Purloin}.]
   1. Drawn out in a line, or in the direction of length;
      protracted; extended; as, a long line; -- opposed to
      short, and distinguished from broad or wide.

Source : WordNet®

longest
     adj : having the greater length of two or the greatest length of
           several; "the longer (or long) edge of the door"; "the
           hypotenuse is the longest (or long) side of a right
           triangle" [syn: {longer}]
     adv : for the most time; "she stayed longest"