Is it ‘premise’ or ‘premises’ when referring to a single property?

Which word is correct?

Just a note on spelling.

In reviewing and editing resumes, cover letters and selection criteria, I occasionally notice the incorrect use of the words ‘premise’ and ‘premises’.

If you’re referring to a house or building – the correct word is: ‘premises’.

For example, “smoking is not permitted on the premises”.

I notice job applicants – as well as advertisers – using the word ‘premise’ as the singular of the word ‘premises’ when referring to a single building or property.

However, even in the case of a single property – the correct word is ‘premises’, e.g. “The real estate agent saw us off the premises.”

The word ‘premise’ is used when referring to the basis for a statement or proposition, e.g. “If the premise is accurate, then the number of COVID-19 cases is falling.”