How do you know if the floors in your house are hardwood?

Nowadays, "hardwood" is a generic term used for any type of wood flooring. Woods such as pine are considered soft woods but are still used as "hardwood" flooring. In my experience any floor that has finished wood covering the surface is a hardwood floor.

The term is used more loosely today. 50 years ago, a "hardwood" floor meant maple, in almost all cases. Today, man-made laminate "wood" might be called a "hardwood" floor, but flooring that is actual pieces of wood will almost always be called a "hardwood" floor. The "finish" floor in most construction nowadays is plywood. The flooring - wood, vinyl, carpeting, whatever - is put down over that.