The Collaborative International Dictionary of English v.0.48:

Essay \Es"say\, n.; pl. Essays. [F. essai, fr. L. exagium a
   weighing, weight, balance; ex out + agere to drive, do; cf.
   examen, exagmen, a means of weighing, a weighing, the tongue
   of a balance, exigere to drive out, examine, weigh, Gr.
   'exa`gion a weight, 'exagia`zein to examine, 'exa`gein to
   drive out, export. See Agent, and cf. Exact, Examine,
   Assay.]
   1. An effort made, or exertion of body or mind, for the
      performance of anything; a trial; attempt; as, to make an
      essay to benefit a friend. "The essay at organization."
      --M. Arnold.
      [1913 Webster]

   2. (Lit.) A composition treating of any particular subject;
      -- usually shorter and less methodical than a formal,
      finished treatise; as, an essay on the life and writings
      of Homer; an essay on fossils, or on commerce.
      [1913 Webster]

   3. An assay. See Assay, n. [Obs.]

   Syn: Attempt; trial; endeavor; effort; tract; treatise;
        dissertation; disquisition.
        [1913 Webster]