In our modern world, the flight booking reference consists of a seemingly random combo of six letters and numbers, so on booking my recent flights for Istanbul I was impressed to find the last three letters

FND

which one might suppose to be a quaint honorific that is tailor-made for a trip to Turkey… Surely a one-off, but charming.

Dede Efendi (d.1846), Mevlevi music master. Source.