Credential means any or all of the following:
(1) Merchant mariner's document.
(2) Merchant mariner's license.
(3) STCW endorsement.
(4) Certificate of registry.
(5) Merchant mariner credential.
46 CFR § 125.160
Each term defined elsewhere in this chapter for a particular class of vessel applies to this subchapter unless a different definition is given in this section. As used by this subchapter -