Monodraw

Maybe just semantics? I think "license" is more technically correct. Even in the best consumer case, you are only "buying" a perpetual right to use a software product. Optionally, you might also get updates.

In the US, the First-Sale Doctrine won't apply to software (unlike tangible books and records) so you probably do not have the right to sell your copy of this software to another person.

Since that's not true ownership, I think it can only be described as a license.

But I'll agree that all sorts of shenanigans can, and often do, hide under that generic term. However, "buy" could suggest many substantial rights that are not on offer (most importantly distribution), so it's a bit of a quandary.

The phrase "Buy Now - $9.99, yours forever" might thread the needle. The sale page would still need to include all the legal terms, of course. I think "license" is a necessary word there.

Personal pet peeve, but the word people use really should be "lease." Copyright and patent rights are licensed (e.g. getting a license from Disney to manufacture Star Wars toys). The particular copy of the software you have is either sold or leased to you. If you buy a physical book, you are just being sold a copy. The book itself doesn't function as an ad hoc, theoretical license or anything.

Not sure how first sale affects software sales other than software rental in the USA is an exception to the first sale doctrine. Software rental is not allowed unless it's a physical video game copy for a video game console or you have a physical copy of the software and you can't just easily make a copy of it in the normal course of using it (not sure exactly what this would mean, but presumably things like software for embedded devices). There are exceptions for libraries and educational institutions.

I am not a lawyer, however.

A lease implies a limited term though, doesn't it?

A perpetual, irrevocable, lease could be a thing.

A perpetual, irrevocable "lease" is just be a "sale". You are just selling a copy at that point. Subscription-based/SAAS software is leased.

I know it's pedantic, but to me the key thing is that it is the rights themselves that are "licensed." Not specific copies. The license covers what ways you are and are not allowed to make more copies (that aren't just your personal copy). So e.g. Open Source/Free Software/Closed Source libraries can be "licensed" and copies of them can be modified and included in work you create according to the license.

I'm here for the pedantry! :)

But I don't think the software of a SaaS is leased, sold, or licensed. It's just a service that is available and perhaps promised to stay available for a term. And of course Monodraw is not a SaaS anyway.

Also not a lawyer. I have read more contracts than most healthy adults, but that is just as likely to be distorting as clarifying.