What is the Application Number, and how is it different from the Patent Number?

It may be understood that patent no. and application no. for each patent are different. Application Number is the number given by patent office at the time of receipt of application for patent, while the Patent Number is the number given when the patent is granted after fulfilling all the requirements of patent office. Application Number is usually in the form of, e.g., US 14/556,894; “US” refers to the Country Code (in this case – United States) and “14/556,894” is the serial no. of the application. It may be noticed that the first two digits of the application number provides the year when the application was made, in this case 2014.