What are #Bitcoin Address D?

Script

Bitcoin uses a scripting system for transactions. Forth-like, Script is simple, stack-based, and processed from left to right. It is intentionally not Turing-complete, with no loops.

A script is essentially a list of instructions recorded with each transaction that describe how the next person wanting to spend the Bitcoins being transferred can gain access to them. The script for a typical Bitcoin transfer to destination Bitcoin address D simply encumbers future spending of the bitcoins with two things: the spender must provide

a public key that, when hashed, yields destination address D embedded in the script, and

a signature to prove ownership of the private key corresponding to the public key just provided.

Scripting provides the flexibility to change the parameters of what's needed to spend transferred Bitcoins. For example, the scripting system could be used to require two private keys, or a combination of several keys, or even no keys at all.