What is Bitcoin?
Bitcoin is a cryptocurrency, a form of electronic cash. It is a decentralized digital currency without a central bank or single administrator that can be sent digitally from user-to-user on the peer-to-peer Bitcoin network without the need for intermediaries.
A Bitcoin Address is an ID of 26-35 alphanumeric numbers, that represents a possible destination for an (incoming) Bitcoin payment for example to a Bitcoin Wallet. A Bitcoin wallet address, which is a hash of the corresponding public key, always starts either with number 1 or with the number 3.