A lexicon is the systematically organized inventory of words, phrases, and meanings that a language or domain maintains. It is not a single physical object but a shared cognitive and cultural artifact: the vocabulary that speakers know, the glossary that disciplines use, the dictionary that records them. Its parameters are membership (which terms qualify as belonging), structure (how terms are ordered — alphabetically, semantically, functionally), and completeness (open-ended for natural languages, bounded for controlled vocabularies). A lexicon persists through teaching (transmission to new speakers), writing (stable external storage), and reference works (dictionaries, glossaries, ontologies that fix a snapshot). It exists as a social contract — each individual's personal lexicon may differ, but the community lexicon persists through agreement.
[formal: lexicon | substrate: mind | horizon: a life | explicit: yes | epoch: 0.21]