Is “premises” always plural?

Question

On-premises ... On-premise

I see these terms frequently used to describe software systems hosted within a company's datacenter vs. software systems hosted externally by a third party (in the "cloud"). The term is also frequently abbreviated to "on-prem" or "OnPrem" or similar with the same meaning. The full spelling is the issue.

I take "premises" means the environ of a company or organization, whereas I take "premise" means the basis for a logical argument.

Is there any valid usage of "premise" sans "S" to mean a company, or is it simply slangy misspelling of "premises"?

Related: As the plural of "premise" in the logical argument sense is "premises", does this cloud the issue a little?

Answer 1

Premises is a curious word. The etymology as far as I understand is something plucked out of a legal document. On the title deed of the document the land or buildings are described at the start, they are the premise, which is to say the stated basis on which the rest of the document is based.

So it might say:

The property at 100 High Street, and surrounding land out, 100 yards
north, and all attached and free standing buildings, including air
rights, and right of free passage to the ajoining highway...

Which is a mouthful. Then the document proceeds:

These premises are rented to the Mr. John Smith, and John Smith
is obliged to maintain these premises in good working order, and
the lawn of the premises must be kept well...

and so forth. The premises is the plural of premise, a legal term meaning the aforementioned thing. This was then plucked out of the contract to be used as a more general term to refer to the property and all the ajoining stuff. Eventually, the word took on a meaning of its own, and came to mean a building, or land or something similar.

So, I suppose the answer to your question is both yes and no. In the idiomatic usage referring to a building or land, it is always plural, but in its origin is can be singular.

Answer 2

Neither premise nor premises actually means a company. Premises refers to

a piece of land together with its buildings, esp considered as a place of business

According to Dictionary.com, both premises (plural noun) and premise (singular noun) can have this meaning. Both can also refer to logical propositions.

The answer I pointed you toward would seem to indicate that on-premise ought to be the proper adjective, although you could probably make a good argument for on-premises if you assert that "premises" in this meaning is a singular collective noun.