# Clause 2 Thirty-one terms, and the four that carry the work

The 2009 edition defines thirty-one terms. Four of them do most of the work in a review: accreditation exponent, adaptation parameter, coupon and witness. Each names a number or a step that a design note will otherwise describe in its own words, and the mismatch is what an auditor finds.

## What it asks

Use the defined terms in the design note and the test plan, and define any local synonym once. Where a term was added or changed by the fourth edition, cite the new definition rather than the 2009 one, and keep the older definition available for systems that have not migrated.

## What the revision does

The fourth edition revisits the term set. The public record does not list the additions or changes, so this page records the 2009 set as the baseline to compare against.

## Who it binds

The author of the internal standard and the reviewer who reads the design note.

## Evidence an auditor samples

- The glossary, with each defined term and the edition it comes from (cryptography standard)
- The design note that uses the terms consistently (architecture)
- The mapping from local synonyms to defined terms (engineering wiki)

## The test you can run

Take a design note and underline every noun that names a number or a step. If any of them is not a defined term, the note is speaking its own language.

## Common failures

- The glossary is copied from a textbook rather than the edition in force.
- A local synonym is used in the test plan and the defined term in the design note.

## How to close it

Keep one glossary per edition and link it from every document. A term is not adopted until the design note, the test plan and the code comment use the same word for the same object.

## Source

ISO/IEC 9798-5:2009(E), Clause 2, publisher preview; replaced by ISO/IEC DIS 9798-5, stage 40.20. Read on 21 October 2026. Our wording, not the instrument's.
https://www.iso.org/standard/89516.html

Not legal advice; does not certify.