Definitions

These are the terms specific to this work. Other terms, such as reference, expansion, repo version and HEAD, mean what they mean in OCL.

Term	Meaning
Dictionary	For this work, a collection with at least one ranked source.
Ranked list	The collection's sources in order of preference, also called the ranked repo list. When concepts are equivalent, the one from the highest-ranked source wins. See Requirements.
Equivalency	Two concepts in different repositories are equivalent when a SAME-AS mapping links them, meaning they mean the same thing. In a collection-based dictionary, equivalency decides which of the two goes into the expansion: the one from the higher-ranked repository in the collection's ranked list. Rules 1 and 2 on the Rules page make this precise.
Equivalency-aware expansion	An expansion that applies the equivalency rules while it resolves references and cascades.
Equivalent duplicates	Two equivalent concepts in the same dictionary, such as PIH:1065 Yes and CIEL:1065 Yes. The rules exist to prevent them.
Replacement	The concept from a higher-ranked source that an expansion contains in place of an equivalent concept from a lower-ranked one (Rule 2).
Referenced concept	The concept a reference names, or that a cascade reached in the source it came from.
Cascade	Following a concept's Q-AND-A mappings (to its answers) and CONCEPT-SET mappings (to its set members), level by level.

Notation: CIEL:1065 means the concept with ID 1065 in the CIEL source. ≡ means "equivalent to".