What is a Software License?

Is it what you've purchased? (aka.  What the purchasing department tracks via a Purchase Order)

Is it what you've installed? (aka. What your inventory software detected)

Is it what's being used? (aka. What your license manager or reporting tools are showing)

Is it a document that defines what, how many, and where you "should" have installed the product? (aka. An SLA or license key file)

Is it a definition of what you are allowed to do with the product?  (aka. A license agreement document)

Is it a bundle of products, or a single product?

Is it a standalone license, or a "floating" networked, pool of licenses?

Is it just an idea, or is it a tangible entity?

Can you hold it in your hands, or does it only exist as an arrangement of electrons?