From Longman Dictionary of Contemporary Englishpetty cashˌpetty ˈcash noun [uncountable] BBTMONEYa small amount of money that is kept in an office for making small payments
Examples from the Corpus
petty cash• Completion and interpretation of petty cash transactions. 3 Materials and Stationery Use and control; methods of economy.• We now have to buy it from our petty cash.• If you work in retailing, you may be asked to look after the petty cash.• They are entered in the petty cash book.• This is not a buck here or a buck there in the petty cash till.• These items are usually paid for out of the petty cash.• Borrowing money from colleagues at work, petty cash, or from neighbours is a fast way of making yourself unpopular.From Longman Business Dictionarypetty cashˌpetty ˈcash a small amount of cash that is kept in an office for making small paymentsIn a small office, items like stationery and coffee are usually paid for out of the petty cash. → cash 