is a user created secret phrase that is used to verify identity or generate cryptographic keys

is data that is used to lock and unlock cryptographic functions such as encryption, authentication and authorization.

Password vs Key

Keys are created by algorithms that are designed to make them difficult to guess. They are typically based on random or pseudorandom data.

Passwords aren't as secure as keys as they are created by users. Users commonly use dictionary words and other patterns in passwords that make them easier to guess than keys.

Passwords are also designed to be remembered and are often shorter than keys. For example, an ascii password of 12 characters can be stored in 96 bits. Keys are commonly 128 bits or longer.

Password to Key

Passwords that are used for encryption are typically converted to a key first using a type of algorithm known as a key derivation function. For example, a cryptographic hash function may be used to create keys from passwords.