Ephemeral Key Pair
A key pair, consisting of a public key (i.e., an ephemeral public key) and a private key (i.e., an ephemeral private key) that is intended for a very short period of use. The key pair is ordinarily used in exactly one transaction of a cryptographic scheme; an exception to this is when the ephemeral key pair is used in multiple transactions for a key-transport broadcast. Contrast with a static key pair.
See NIST SP 800-56A Rev. 2 for more information.