Process of exchanging public keys (and other information) in order to establish secure communications.
Sources:
CNSSI 4009-2015
A key-establishment procedure whereby one party (the sender) selects and encrypts (or wraps) the keying material and then distributes it to another party (the receiver).
When used in conjunction with a public- key (asymmetric) algorithm, the key is encrypted using the public key of the receiver and subsequently decrypted using receiver's private key.
When used in conjunction with a symmetric algorithm, the key is encrypted with a key- wrapping key shared by the sending and receiving parties and decrypted using the same key.