Source : Webster's Revised Unabridged Dictionary (1913)

Clerk \Clerk\ (?; in Eng. ?; 277), n. [Either OF. clerc, fr. L.
   clericus a priest, or AS. clerc, cleric, clerk, priest, fr.
   L. clericus, fr. Gr. ? belonging to the clergy, fr. ? lot,
   allotment, clergy; cf. Deut. xviii. 2. Cf. {Clergy}.]
   1. A clergyman or ecclesiastic. [Obs.]

            All persons were styled clerks that served in the
            church of Christ.                     --Ayliffe.

   2. A man who could read; a scholar; a learned person; a man
      of letters. [Obs.] ``Every one that could read . . . being
      accounted a clerk.'' --Blackstone.

            He was no great clerk, but he was perfectly well
            versed in the interests of Europe.    --Burke.

   3. A parish officer, being a layman who leads in reading the
      responses of the Episcopal church service, and otherwise
      assists in it. [Eng.] --Hook.

            And like unlettered clerk still cry ``Amen''.
                                                  --Shak.

   4. One employed to keep records or accounts; a scribe; an
      accountant; as, the clerk of a court; a town clerk.

            The clerk of the crown . . . withdrew the bill.
                                                  --Strype.

   Note: In some cases, clerk is synonymous with secretary. A
         clerk is always an officer subordinate to a higher
         officer, board, corporation, or person; whereas a
         secretary may be either a subordinate or the head of an
         office or department.

   5. An assistant in a shop or store. [U. S.]

Source : WordNet®

clerk
     n 1: an employee who performs clerical work (e.g., keeps records
          or accounts)
     2: a salesperson in a store [syn: {salesclerk}, {shop clerk}]

clerk
     v : work as a clerk, as in the legal business