Etymology of 'Gloss' and 'Glossary': From Greek 'Glossa' (Tongue)

English has two unrelated words spelled gloss. The one familiar from everyday speech means a shiny surface or sheen, and a third, looser sense, 'to gloss over', means to smooth a problem away superficially. That word probably entered English in the 1530s from a Scandinavian source (compare Icelandic 'glossi', a spark or flame) or obsolete Dutch 'gloos', a glow, and is ultimately related to the English verb 'glow' through Proto-Germanic. The other 'gloss' is older and more specialized. It means a brief explanatory note or interpretation of a difficult word or passage, and it is the one a Russian dictionary lists as a translation of 'tolkovanie' (interpretation). It entered English around 1300 in the form 'glose' (the modern spelling 'gloss' dates from the 1540s) and comes from Late Latin 'glossa', meaning an obsolete or foreign word that needs explaining, which in turn comes from Ancient Greek glossa (Ionic) or 'glotta' (Attic), meaning 'tongue, language'. The two homonyms are therefore etymologically distinct: one is Germanic and concrete (shine), the other is Greek-via-Latin and literary (annotation). The core meaning is a Gloss (Annotation): Marginal and Interlinear Notes in Medieval Manuscripts — a short explanation written between the lines or in the margin of a manuscript, typically rendering a hard Latin, Greek, or Hebrew word into the reader's vernacular. Over time the noun broadened to mean any explanatory comment or interpretation ('the editor's gloss on the passage'), and it works as a verb too ('he glossed "eldritch" as weird, uncanny'). From its earliest English use the word also carried a pejorative shading: by the early 14th century a 'gloss' could mean a deceitful or self-serving commentary that disguises or shifts a text's meaning, a sense that survives in the modern phrase 'to gloss over'. The most technical surviving sense is legal. In the tradition of Roman and canon law, a gloss is an authoritative interpretive note attached to a statute or text; the medieval Glossators built an entire scholarly apparatus of such notes, the most famous being the The Glossators and the Glossa Ordinaria: Reviving Roman Law in Medieval Bologna. Glossary comes straight from this word. The chain runs Greek glossa (tongue, and by extension an obscure word needing explanation) into Latin 'glossa' (a word that needs explaining) into Latin 'glossarium' (a collection of such words with their explanations) into Middle English 'glosarie' and modern English glossary. A glossary is literally a collection of glosses. The medieval workflow makes this concrete: a scribe wrote little explanations of hard words in the margins, and eventually those notes were gathered into a separate list — a 'glossarium'. This is why a glossary is not quite a dictionary: a dictionary aims to cover a whole language comprehensively, while a glossary is tied to a specific text or field and explains only the difficult or specialized terms a reader of that work will meet. Medieval glossaries were, in fact, among the earliest precursors of the modern dictionary, and compiling them was the beginning of lexicography. The same Greek root for 'tongue' produces a wider word family: glossolalia (speaking in tongues, literally tongue-speech), 'polyglot' (many-tongued, multilingual), and 'epiglottis' (the flap 'upon the tongue'). The Greek 'glossa' is the literary form; the Attic Greek variant 'glotta' survives in 'epiglottis' and 'polyglot'.