Definition
Do it yourself (DIY) refers to building, repairing or modifying things on your own instead of hiring professionals, with the emphasis on doing it yourself rather than on achieving professional-grade results.
How it works
DIY projects usually start from public tutorials, open-source designs and community discussions; the builder supplies tools and materials and assembles things by hand. In hardware projects, the work often begins with listing the required parts and materials before purchasing them one by one.
Usage
DIY spans home repair, hardware mods, self-hosted software and content creation; when tech circles say “DIY a NAS”, they mean picking the parts, assembling and configuring a storage server yourself.
Related and confusable terms
DIY is the counterpart of outsourcing work to professional services. In hardware contexts, a DIY project usually comes with a bill of materials (BOM) used to check off parts and purchase quantities.