What a requirement covers (includes) and what it excludes. Stating both keeps the requirement from being read wider or narrower than intended. The scope and boundary section of an analysis document is different: it names the entity of interest, what is in and out of scope, the intended use, the intended users by role and the regulated status.
See also: Requirement, Analysis document
Interim definition. BLORP takes this term over when the global ontology lifts from Phase-0.