An online search revealed this answer to that question: “A tube or trough for protecting electric wiring.” To someone untrained in the electrical field, that definition seems correct. But using that definition in electrical work causes confusion. Conduit is a type of raceway, and tubing is another (distinctly different) type of raceway.
What is Conduit?
Conduit is a type of raceway, and tubing is a distinctly different type of raceway.