An address is a string of text or numbers designating a wallet's location on a blockchain. Different blockchains may use different formats for addresses, and addresses are primarily used to send or receive digital addresses.
In the case of Bitcoin, an address is an alphanumeric, base58 identifier derived from the public key (usually the ECSDA public key) that can be given out to another party to send coins to. Valid Bitcoin addresses start with a 1 or 3, but other cryptocurrency addresses may begin with other characters. Addresses usually have a checksum at the end in order to validate them – a single character mistake in copying an address would result in an invalid address and prevent coins from being transferred to an incorrect address. Any standard Bitcoin wallet can generate any number of new addresses. HD wallets allow for the creation of multiple addresses from the same private key. Addresses can also be multi-signature.