definition of the term backup by most sources is one the line of:

> a copy of information held on a computer that is stored separately from the computer

there is nothing about _any_ versioning, or duration requirements or similar

To use your own words, I fear its you who doesn't know what a backup is and assume a lot other additional (often preferable(1)) things are part of that term.

Which is a common problem, not just for the term backup.

There is a reason lawyers define technical terms in a for this contract specific precise way when making contracts.

Or just requirements engineering. Failing there and you might end up having a backup of all your companies important data in a way susceptible to encrypting your files ransomware or similar.

---

(1): What often is preferable is also sometimes the think you really don't want. Like sometimes keeping data around too long is outright illegal. Sometimes that also applies to older versions only. And sometimes just some short term backups are more then enough for you use case. The point here is the term backup can't mean what you are imply it does because a lot of existing use cases are incompatible with it.