Singular or plural?

The other day, I watched a policeman in a TV interview say that officers had searched a premise. Why did I think the word was premises?

I looked it up. Premises refers to a building and the land it stands on, hence two things. Plural.

There is a singular use for the word premise, of course. It is a proposition used as the basis for a conclusion or action.

Here’s my favourite definition of conclusion:
It is the point at which we decide to stop thinking.