An example of a writting instrument can be a pen or pencil.
an instrument
Stylus.
cuneiform
crayon
writing
forgery
A Stylus
A scotograph is an instrument used for writing in the dark.
Peann: pen (writing instrument)
a stylus.
A writing implement or writing instrument is an object used to produce writing. Most can be used for other functions, such as painting, drawing and technical drawing. One of the critical characteristics of a writing implement is the ability to produce a smooth, controllable line. (Wikipedia)All in all, yes it is!
a musical instrument? a wind instrument? a string instrument? a percussion instrument?