As well as being asked “what is a copywriter?“, I am occasionally asked “what is a technical writer?”.
Wikipedia provides the following succinct definition:
“A technical writer is a professional writer who engages in technical writing and produces technical documentation for technical, business, and consumer audiences.”
Someone who writes about technical topics in other words.
The difference between technical writing and technical copywriting
The main difference between technical writing and technical copywriting is the goal of the document being produced. Technical writing is usually about documenting complex systems or providing instructions on their use. Think manuals and tutorials for instance.