[1] : The Collaborative International Dictionary of English v.0.48

petty \pet"ty\ pe^t"ty^, a. compar. pettier
   pe^t"ti^~er; superl. pettiest. oe. petit, f.
   petit; probably of celtic origin, and akin to e. piece. cf.
   petit.
   little; trifling; inconsiderable; unimportant; also,
   inferior; subordinate; as, a petty fault; petty complaints; a
   petty prince. --denham.
   1913 webster

         like a petty god
         i walked about, admired of all.          --milton.
   1913 webster

   petty averages. see under average.

   petty cash, money expended or received in small items or
      amounts.

   petty officer, a subofficer in the navy, as a gunner, etc.,
      corresponding to a noncommissionned officer in the army.
      1913 webster

   note: for petty constable, petty jury, petty larceny, petty
         treason, see petit.
         1913 webster

   syn: little; diminutive; inconsiderable; inferior; trifling;
        trivial; unimportant; frivolous.
        1913 webster
see also:
pettier pettiest petit petty averages average petty cash 
petty officer 

[2] : WordNet (r) 2.0

petty cash
     n : a small fund of cash that a firm keeps for the payment of
         incidental expenses

Petty Cash >> P Words
Petty Cash, definition of term: Petty Cash
petty+cash_pag1.html

Petty >> P Words
Petty, definition of term: Petty
petty_pag1.html

Cash >> C Words
Cash, definition of term: Cash
cash_pag1.html

Petty Larceny >> P Words
Petty Larceny, definition of term: Petty Larceny
petty+larceny_pag1.html

Cash Cow >> C Words
Cash Cow, definition of term: Cash Cow
cash+cow_pag1.html

Cash Advance >> C Words
Cash Advance, definition of term: Cash Advance
cash+advance_pag1.html

Cash Basis >> C Words
Cash Basis, definition of term: Cash Basis
cash+basis_pag1.html

Cash Register >> C Words
Cash Register, definition of term: Cash Register
cash+register_pag1.html