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,
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."
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.
3. An assay. See Assay, n. [Obs.]
Syn: Attempt; trial; endeavor; effort; tract; treatise;