"on-premise" - I think they actually mean on-premises. A premise and a premises are not the same thing. I see this mistake made all too often.
It's close enough that everyone knows what it means, but it's not right.
I wonder if there's a term, similar to "backronym", when the singular form of a word is derived from casual mutation from its plural?
Of course! The premises are "the matter previously stated" on a property deed.
I did a very shallow search and nothing came up, thanks for pointing me in the right direction.
>I wonder if there's a term, similar to "backronym", when the singular form of a word is derived from casual mutation from its plural?
I think premises/premise(s) might be unique in English in that it's a singular noun, pluralized by adding an s, where the plural form is a homonym with another singular noun that is dissimilar in meaning to the root singular noun. Lots of words hit 2/3, but I can't think of any others that are all 3.
If you're talking about a declarative statement used as the foundation of an argument, use "premise".
Examples:
"Were those databases moved to the cloud?"
"No, they're still on the premises." (Premises = place)
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"Why did we decide to move those DBs to the cloud?"
"On the premise that it's cheaper than managing the server administration ourselves." (Premise = something stated as the basis for an argument)
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"Can you give me a few more reasons that we moved those DBs to the cloud for the executive committee meeting?"
"We made the decision on the premises that it's cheaper to run, our basement server room regularly floods, and our current server admin is a drunk." (Premises = plural of premise)