I'll repeat my answer from the last thread...In respect to airman, the FAA doesn't certify anyone. Instead, they have been issued a certificate confirming that they demonstrated the ability to meet at particular minimum standard. The reason for the difference is to convey that there is no assurance or guarantee that the airman consistently and continuously meets this standard. It's not like a "certified used car"...the FAA is not going to give you your money back if the pilot crashes the plane you're flying in.
The FAA doesn't certify airman, period. That FAA acronym list cited previously is incorrect, and isn't maintained as part of the official list of documents (orders, ACS etc.) that are updated whenever changes due to policy or rulemaking take place. The list is from FAA HR folks, who well, you know...probably aren't exactly the authority on matters such as this.