The Collaborative International Dictionary of English v.0.48:

Purser \Purs"er\, n. [See Purse, and cf. Bursar.]
   [1913 Webster]
   1. (Naut.) A commissioned officer in the navy who had charge
      of the provisions, clothing, and public moneys on
      shipboard; -- now called paymaster.
      [1913 Webster]

   2. A clerk on steam passenger vessels whose duty it is to
      keep the accounts of the vessels, such as the receipt of
      freight, tickets, etc.
      [1913 Webster]

   3. Colloquially, any paymaster or cashier.
      [1913 Webster]

   Purser's name (Naut.), a false name. [Slang]
      [1913 Webster]

WordNet (r) 3.0 (2006):

purser
    n 1: an officer aboard a ship who keeps accounts and attends to
         the passengers' welfare

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "purser":
   accountant, auditor, bakehead, black gang, boilerman, bookkeeper,
   bungs, bursar, cabin boy, cashier, cashkeeper, chamberlain, chips,
   commissary steward, compensator, complement, comptroller,
   controller, curator, deckhand, deckie, defrayer, depositary,
   depository, financial officer, fireman, gun loader, gunner, hand,
   hospital steward, landing signalman, liquidator, mail orderly,
   navigator, oiler, payer, paymaster, purse bearer, radio operator,
   ratepayer, receiver, recompenser, remunerator, roustabout, snip,
   snips, sparks, steward, stewardess, stoker, taxpayer, torpedoman,
   treasurer, trustee, watch, yeoman



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PURSER. The person appointed by the master of a ship or vessel, whose duty
it is to take care of the ship's books, in which everything on board is
inserted, as well the names of mariners as the articles of merchandise
shipped. Rosc. Ins. note.
     2. The act of congress concerning the naval establishment, passed March
30, 1812, provides, Sec. 6, That the pursers in the Navy of the United
States shall be appointed by the president of the United States, by and with
the advice and consent of the senate; and that, from and after the first day
of May next, no person shall act in the character of purser, who shall not
have been thus first nominated and appointed, excepting pursers on distant
service, who shall not remain in service after the first day of July next,
unless nominated and appointed as aforesaid. And every purser, before
entering upon the duties of his office, shall give bond, with two or more
sufficient sureties, in the penalty of ten thousand dollars, conditioned
faithfully to perform all the duties of purser in the United States.
     3. And by the supplementary act to this act concerning the naval
establishment, passed March 1, 1817, it is enacted, Sec. 1, That every
purser now in service, or who may hereafter be appointed, shall, instead of
the bond required by the act to which this is a supplement, enter into bond,
with two or more sufficient sureties, in the penalty of twenty-five thousand
dollars, conditioned for the faithful discharge of all his duties as purser
in the navy of the United States, which said sureties shall be approved by
the judge or attorney of the United States for the district in which such
purser shall reside.