A diplomatic edition is an edition which is based on a single manuscript and usually follows it very closely in matters of orthography, so that it is suited for e.g. linguistic studies. In many cases, obvious mistakes are not corrected, but perhaps only pointed out in the apparatus.
Diplomatic editions are particularly frequent in the field of vernacular languages, since many of these lack a standard orthography. The editor then has to chose between the orthography of the manuscript or some type of regularised orthography and will often find the first solution easiest and also truest to the source.
The term derives from Latin diploma, originally a folded piece of writing material, and by extension to the study of the writing on such documents. The term diplomatics was coined by the Benedictine monk Jean Mabillon in his influential treatise De re diplomatica (1681), in which he developed the study of written documents with regards to their script, date and authenticity, and a diplomatic edition is thus an edition suited for this kind of study. The term diplomacy in the meaning ‘the managing of international relations’ has the same root in the word diploma, although it has acquired a quite different meaning.
For a fuller discussion of the term, see editions, types of.
In other languages
DE: diplomatische Edition
FR: édition diplomatique
IT: edizione diplomatica