Autograph authentication glossary
Clear, plain-English definitions of the terms every collector should know — from COAs and LOAs to witnessed certification, slabbing and more.
Certificate of Authenticity (COA)
The certification record + tamper-evident sticker tied to an item's unique serial number.
A Certificate of Authenticity (COA) is the core certification record for a signed collectible. At MAS, each COA is linked to a unique serial number and a tamper-evident sticker, and can be independently verified for free in real time at the public MAS COA lookup.
Letter of Authenticity (LOA)
A detailed signed letter — digital or printed — that accompanies higher-value items.
A Letter of Authenticity (LOA) is a detailed document describing a certified item and its authentication. MAS offers both digital LOAs (delivered electronically) and physical LOAs (a printed letter) as optional upgrades to a standard COA.
Witnessed Authentication
Certification where an authenticator was physically present at the signing.
Witnessed (in-person) authentication means an MAS representative personally observed the item being signed — at a convention, private signing, or in-store event. Because the signing is seen first-hand, there is no opinion or guesswork, making it the strongest standard in the autograph hobby.
Slabbing
Sealing a collectible in a rigid, tamper-evident protective case.
Slabbing is the process of encasing a card or collectible in a rigid, tamper-evident holder. MAS grading pairs a protective slab with a holographic, publicly verifiable COA so items are protected and authenticated for life.
Autopen
A machine that reproduces a signature; not a genuine autograph.
An autopen is a mechanical device that reproduces a person's signature. Autopen signatures are not authentic autographs and often reveal themselves through uniform line weight and identical, repeatable shapes across multiple items.
Secretarial Signature
A signature signed on someone's behalf by an assistant or staff member.
A secretarial signature is one signed by an assistant or staff member on behalf of a celebrity or athlete. While historically common for fan mail, secretarial signatures are not authentic autographs and are distinguished through expert examination.
Sticker Autograph
A signature applied to a label that is later placed on a card by the manufacturer.
A sticker autograph is signed on an adhesive label that a card manufacturer later applies to a card, as opposed to an 'on-card' autograph signed directly on the card surface. Both are genuine, but on-card signatures are often valued more highly.
On-Card Autograph
A signature applied directly to the card's surface.
An on-card autograph is signed directly onto the card rather than on a sticker. Collectors frequently prefer on-card autographs for their appearance and perceived value.
Inscription
Extra text added with a signature, such as a stat, quote, or dedication.
An inscription is additional handwriting accompanying a signature — for example a stat line, nickname, quote, or personalization. Inscriptions can add meaning and, in some cases, value to a signed item.
Provenance
The documented history of where and how an item was obtained.
Provenance is the record of an item's origin and ownership history. While helpful context, provenance alone is not proof of authenticity — verifiable certification provides far stronger protection for buyers and sellers.
Population Report
A tally of how many items an authenticator or grader has certified.
A population report tracks how many examples of a given item have been certified or graded. Population data helps collectors understand relative scarcity within a certification service.
Tamper-Evident Seal
A sticker or holder that shows visible evidence if someone tries to remove it.
A tamper-evident seal is a sticker or case designed to reveal any attempt to remove or alter it. MAS uses tamper-evident COA stickers and holders so collectors can trust that a certified item has not been swapped or compromised.
Put it into practice
Verify a certificate or submit an item for professional authentication.