An ordered sequence of certificates, leading from a certificate whose public key is known by a client, to a certificate whose public key is to be validated by the client.
NIST SP 800-15
A chain of trusted public-key certificates that begins with a certificate whose signature can be verified by a relying party using a trust anchor, and ends with the certificate of the entity whose trust needs to be established.
NIST SP 800-152 under Certification path
An ordered list of certificates (containing an end-entity subscriber certificate and zero or more intermediate certificates) that enables the receiver to verify that the sender and all intermediate certificates are trustworthy. Each certificate in the path must have been signed by the private key corresponding to the public key contained in the certificate that precedes it in the path, and the first certificate in the path must have been issued by a Trust anchor.
NIST SP 800-57 Part 2 Rev.1 under Certification path