What is the best definition for technical writing?

Technical writing is a type of writing where the author is writing about a particular subject that requires direction, instruction, or explanation. This style of writing has a very different purpose and different characteristics than other writing styles such as creative writing, academic writing or business writing.

Technical writing is any written form of writing or drafting technical communication used in a variety of technical and occupational fields, like as computer hardware and software, engineering, chemistry, aeronautics, robotics, finance, medical, consumer electronics, and biotechnology. It encompasses the largest sub-field within technical communication. i hope that helps