Yes, Lucero Tena plays the castanets. In Spanish, "castañuelas". Check her out on YouTube. She plays the castanets for flamenco as well as Classical Music. She is fantastic!
synthesizer
A short musical idea can be called a number of things. It can be called a phrase or motif for example.
An "understudy."
You might be talking about maracas.
It is called a 'score'
Whip is a percussion instrument. It is also called a slapstick.
Strings
a musical instrument? a wind instrument? a string instrument? a percussion instrument?
It is called an ocarina.
They can be called Instrument Makers.
Jazz is a type of music not a musical instrument.
banjo.
Usually, they are called a musician.
It's not a musical, but theres a play called Quillters.
There is a musical instrument called a triangle, it is both shaped, and named, the same as the three-sided figure itself.
Playing a stringed instrument by plucking the strings is called 'pizzicato'.
it's called a stylophone