Private key
A secret number that proves ownership of Bitcoin and authorizes transactions. Whoever holds the private key controls the funds.
cypherpunk
Definition
A cypherpunk is a member of an informal community of cryptographers, programmers, and privacy activists who believed strong cryptography was essential for personal freedom. The movement began in the early 1990s and produced many of the cryptographic ideas that Bitcoin later built on.
Example
Cypherpunks on a mailing list in the 1990s developed many of the ideas that later became Bitcoin.