Gloss originally denoted an obsolete or an unusual word in an author's text, or a word in a foreign text requiring explanation, but was afterwards applied to the explanation itself. Collections of glosses on the early Greek poets abounded during the Alexandrian period. The Rabbinical writers expended the same care on the text of the Hebrew Scriptures, and there were numerous glossarians of the Latin Vulgate. Glosses of a different kind, interpreting the matter rather than the words, were inserted by the jurists in the MSS. of Roman and canon law, either on the margin or between the lines. The explanations of Latin, Greek, or Hebrew words by their Teutonic, Keltic, or Romance equivalents or vice versa in mediaeval MSS., sometimes furnish a valuable clue in etymological researches.