It can mean the type of tool, e.g. a wrench that’s well made from good quality steel, but has a simpler finish such as black oxide, might be termed an industrial tool. Snap On “Industrial Finish” wrenches are an example.
It can also mean a manufacturer that makes high quality tools, but sells direct to bigger “Industrial” customers, or through distributors, rather than from a tool truck. Proto is actually a great example, you can pretty much buy the tools anywhere (no doubt direct and at a discount if you buy enough) but they are very similar to Mac, that are sold from tool trucks, with a lifetime warranty, at higher price. Similar tools, different business model.