playbooks
A musical pieces intended as practice aid is called an étude.
They can be called Instrument Makers.
it is called the mouth of the river
The C minor equivalent of a given musical key is B major.
The military position given to Josephus was that of Roman Procurator of Judea. This is considered the beginning of the Jewish Wars, and the first Jewish-Roman War, in history.
spring
Frontis piece is the illustration at the beginning of a book
They were called Cavaliers, originally as a term of abuse!
A slide, for example on a trombone, is called a glissando. I guess you could use the same term on a stringed instrument like guitar.
The letters in music are called the musical alphabet. The letters represent notes, and there are 12 of them. Natural notes are given the letters A through G. The other notes are in between natural notes and they are called sharps and flats.
Odeon
The bailiff's opening announcements are typically called "opening instructions" or "jury instructions." These are given at the beginning of a trial to provide guidance to the jury about their roles and responsibilities during the proceedings.