Clarify complete vs self-contained documents

Author: handrews

versions/3.1.1.md

@@ -123,7 +123,9 @@ In order to preserve the ability to round-trip between YAML and JSON formats, YA
 
 An OpenAPI Description (OAD) MAY be made up of a single document or be divided into multiple, connected parts at the discretion of the author. In the latter case, [Reference Object](#reference-object), [Path Item Object](#path-item-object) and [Schema Object](#schema-object) `$ref` keywords, as well as the [Link Object](#link-object) `operationRef` keyword, are used.
 
-Any document consisting entirely of an [OpenAPI Object](#openapi-object) is known as a **complete OpenAPI document**.
+Any document consisting entirely of an [OpenAPI Object](#openapi-object) is known as a **syntactically complete OpenAPI document**.
+An OpenAPI document that does ***not*** reference any other documents is known as a **self-contained OpenAPI document.***
+A single-document description is therefore _both_ syntactically complete _and_ self-contained.
 In a multi-document description, the document containing the OpenAPI Object where parsing begins for a specific API's description is known as that API's **entry OpenAPI document**, or simply **entry document**.
 
 It is RECOMMENDED that the entry OpenAPI document be named: `openapi.json` or `openapi.yaml`.
@@ -157,7 +159,7 @@ It is the responsibility of an embedding format to define how to parse embedded
 
 When parsing an OAD, JSON or YAML objects are parsed into specific Objects (such as [Operation Objects](#operation-object), [Response Objects](#response-object), [Reference Objects](#reference-object), etc.) based on the parsing context. Depending on how references are arranged, a given JSON or YAML object can be parsed in multiple different contexts:
 
-* As a complete OpenAPI Description document
+* As a syntactically complete OpenAPI Description document
 * As the Object type implied by its parent Object within the document
 * As a reference target, with the Object type matching the reference source's context