An example of a writting instrument can be a pen or pencil.
an instrument
cuneiform
Stylus.
crayon
writing
forgery
A Stylus
Peann: pen (writing instrument)
a stylus.
A scotograph is an instrument used for writing in the dark.
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!
It is a tool for comm; that is, a writing instrument.