A premise is a proposition that an argument rests on — the premise of the study. Premises means a building and its grounds, and is always plural in that sense: "the premises are locked", never "the premise is locked". One building, plural word.
The core difference
Two senses of the same word, one of which is grammatically plural regardless of how many buildings you mean.
- premise — a proposition underlying an argument: a false premise. Plural: premises, in the logical sense too.
- premises — a building and its land: vacate the premises. Always plural.
How a building became plural
Through law. Property deeds set out the terms first, then referred back to "the premises" — meaning the things previously stated. Because those statements described the property, the word transferred to the property itself, keeping the plural form it had in that legal usage.
The trap
"Our premise on the high street" is wrong even for a single shop. It is always premises, and it takes a plural verb.
Frequently asked questions
Can I say "a premise" for one building?
No. In the property sense the word is always premises, and takes a plural verb.
Why is premises plural?
It comes from legal deeds, where "the premises" meant the matters previously stated. The plural carried over to the property itself.
What is a premise in an argument?
A proposition the argument rests on — a false premise leads to an unreliable conclusion.