In short IP stands for Internet Protocol. IP by itself is a very big topics so what I’m going to explain here is going to be in very layman so all non techie could understand what IP means.
Each computer, server or devices (printers and other network equipment) is represented by an IP address when connected together in a network. Its only possible for computers to talk to each other in a network. An IP address took the form nnn.nnn.nnn.nnn where n is an integer from the range of 0 to 255.
How IP works during surfing?
To keep things simple, let say I want to sign on to the Internet to search for “coffee maker”. So I turn on the computer and sign on to the Internet. As soon as I sign on, my computer will be assigned a set of unique temporary IP address by the Internet Service provider.
When I entered a set of search query to Google, Google will know that my computer has issue a query and return their findings to my computer via my computer’s IP. The results would be direct to the wrong computer because my temporary IP that assigned to my computer when I first signo are unique throughout the while Internet.
But don't get confuse though, IP could also means Intellectual Properties. It is commonly use by lawyers and it is possible they've been using IP long before techie do. But we techies prove later on that we uses it more in a fashionable way too often then the lawyers do. For the younger generation nowdays IP means Internet Protocol make more sense than Intellectual Properties. :)