Closing is where ownership of the home is legally transferred from the seller to the buyer. It is a formal meeting in which most parties involved in the buying/selling process will attend. Closing procedures are usually held at the title company's office or lawyer's office. Your closing officer coordinates the document signing and the collection and disbursement of funds. 
In order for the closing to go smoothly, each party involved should bring the necessary documentation and be prepared to pay any related fees (closing costs). There may be more than one form of acceptable payment for your closing costs so ask the closing officer which form of payment will be required and to whom it should be paid.