Plain English Meaning
Pilots who are licensed by the FAA not just to fly, but to teach others how to fly and to sign them off when they are ready to take their tests.
Full Definition
Pilots who hold an FAA flight instructor certificate authorizing them to provide flight and ground training to student and rated pilots, and to endorse them for solo flight, checkrides, and additional ratings.
Context Anchor
Seen in training and aeronautical decision-making discussions when pilots are encouraged to use knowledgeable people as information resources.
Derivation
Certificated comes from the Latin certificare, meaning to make certain or to attest. A CFI has been formally attested by the FAA as qualified to instruct. The word certificated (rather than certified) is the FAA's preferred legal term for someone who holds an official FAA certificate.