What is a gloss in literature?

In literature, linguistics, and academic study, a gloss is a brief explanation, definition, translation, or annotation of a word, phrase, or passage that might be difficult, obscure, archaic, or in a foreign language. Glosses originated in ancient manuscripts where scribes would write notes in the margins or between lines to help readers understand the text. There are several types. An interlinear gloss appears between lines of text, often providing a word-for-word translation. A marginal gloss appears in the margin. A glossary is a collection of such glosses, usually alphabetized at the end of a book. In linguistics, glossing is used to show the grammatical structure of sentences in unfamiliar languages by providing morpheme-by-morpheme translations. In medieval literature, famous examples include glosses on the Bible, where scholars added commentary to explain theological meaning. The purpose of a literary gloss is to make a text more accessible without rewriting the original, preserving the original wording while adding a layer of understanding. So a gloss is essentially a helpful explanatory note that clarifies meaning.