Diple
Medieval repeat sign.
What it means
Diple designates a sign of medieval manuscripts that in musical texts is interpreted as an indication of a repeat. The name goes back to a sign of ancient and medieval writing practice that originally served as a reference mark in the margin of texts. Its use in a musical context is not transmitted uniformly, and meaning as well as scope vary from source to source.
In the notation
The sign is described as a small angle or double stroke that stands in the margin or above the spot concerned and indicates that the following or preceding section is to be performed once more. It has no fixed form valid across all manuscripts; whoever works with such sources depends on the indications of the respective editor. It differs from the modern repeat sign — a double bar with two dots — both in shape and in bindingness: the latter is unambiguous and standardized, the former remains in need of interpretation.
Musical use
The point of such signs lies in the economy of the manuscript: parchment was expensive, and a recurring line of melody — for instance in strophically laid-out sacred songs or in refrain forms — did not have to be written twice. In the practical use of present-day editions, such places usually appear written out, so that the reader no longer sees the underlying marking at all; the critical report then notes where a shorthand stood in the original.
As a sign, the diple comes from ancient textual criticism, where it gave indications of noteworthy passages in the margin. In musical manuscripts of the Middle Ages it was used in different ways. The interpretation in an individual case therefore depends on the source.
Performance practice
If you meet the term in an editor's report, check which repeat the edition has derived from it and whether it is marked as secure or as a suggestion — with strophic pieces this decides the form of the whole performance. For the study, rely on the written-out notation of the edition and consult the ensemble director before you add or cut a repeat on your own authority.