Add a Glossary page with 2 initial entries.

Doing so should hopefully now allow farming out additional
entries.

Refs: json-schema-org/community#199.

Author: Julian

learn/glossary.md

@@ -0,0 +1,33 @@
+# JSON Schema Glossary
+
+This document collects short explanations of terminology one may encounter within the JSON Schema community.
+
+Whilst many of the entries below have precise technical definitions, preference is given to explanations of their conversational use, with additional references linked for further information.
+This page is not meant to be [normative](#normative), nor is it meant to contain fully original research or explanation.
+It is meant to aid the understanding of those less familiar with formal language used within JSON Schema, or within specifications more broadly.
+(In fact, entries below make effort to avoid terminology like "normative" itself for reasons just mentioned.)
+
+The entries on this page can be linked to via anchor links (e.g. `https://json-schema.org/learn/glossary.html#vocabulary`) when sharing a definition with others.
+
+### draft
+
+An individual release of the JSON Schema specification.
+
+JSON Schema drafts are not intended to be provisional documents, as the layman's use of the word "draft" might indicate.
+
+While future drafts may introduce new behavior or changes to existing behavior, each draft is a completed, released document, batching together changes to the specification, and intended for implementation and use.
+
+The current list of drafts can be found [here](https://json-schema.org/specification-links.html#published-drafts).
+
+### normative
+
+In the context of JSON Schema, and formal specifications more broadly, a document which outlines standardized behavior.
+This is as distinct from *non*-normative or informational documents, meant to explain, simplify or offer opinions.
+
+Distinguishing between whether a document is normative or not is intended to clarify to those using the document whether its contents are allowed to contradict or augment behavior described in other normative documents.
+JSON Schema's normative documents notably include its [specification](https://json-schema.org/specification.html).
+This page for instance, not being a normative document, is not able to proscribe new JSON Schema behavior not already covered by the specification.
+
+##### See also
+
+* [normative](https://developer.mozilla.org/en-US/docs/Glossary/Normative) and [non-normative](https://developer.mozilla.org/en-US/docs/Glossary/non-normative) in the Mozilla Glossary, and its links

learn/index.md

@@ -12,3 +12,4 @@ title: Learn
   * [card.schema.json](./examples/card.schema.json)
   * [geographical-location.schema.json](./examples/geographical-location.schema.json)
 * [Understanding JSON Schema](/understanding-json-schema/)
+* [JSON Schema Glossary](./glossary.md) which attempts to explain conversational terminology