Wiki · Reference entry
Anchor
A requirement, written down, that the system can be checked against.
Our word for the unit of intent. An anchor starts life as a hypothesis, becomes confirmed or discarded, and once confirmed it never stops applying: it turns into a standing obligation that later changes have to keep satisfying. A requirement that is not an anchor is a requirement you will break without noticing.
Why it matters
Discovery is worthless if what you discovered is not written somewhere durable.