What is a gloss in the Bible?

In the Bible, a gloss refers to an explanatory note, addition, or commentary that was inserted into the biblical text by a copyist, translator, or editor over centuries of manuscript transmission, often originally intended as a marginal explanation that later got copied into the main text. Biblical scholars study glosses to understand how the text evolved. For example, some manuscripts of the New Testament contain marginal notes explaining a difficult word, and later copyists mistakenly incorporated those notes into the body of the text. These are called textual glosses. There are also theological glosses, where a scribe added a clarifying phrase to explain doctrine. A famous debated example is the longer ending of certain verses where explanatory phrases may have been added. In modern study Bibles, a gloss can also simply mean a brief definition in the margin or footnote that explains an archaic term, such as explaining that cor means a measure of grain. Additionally, interlinear glosses are used in Hebrew and Greek study to show literal translations. So in biblical studies, a gloss is not part of the original inspired text but an added layer of interpretation or explanation that helps readers, though scholars work to distinguish original text from later glosses.