Whether a contract term is ambiguous is a question of law for the court, and the answer decides who interprets the contract. An unambiguous contract is construed by the judge, often on summary judgment. An ambiguous one usually goes to the factfinder with extrinsic evidence.

The standard. A term is ambiguous when it is reasonably susceptible to more than one meaning. That two parties now argue for different readings proves nothing; litigants always do. The competing readings must each be reasonable in context.

Patent and latent ambiguity. A patent ambiguity appears on the face of the document — two clauses that cannot both be true. A latent one appears only when the contract meets the world, as when a description fits two different parcels.

What courts read first. The whole document, not the disputed sentence alone. Provisions are read to give effect to every clause where possible, specific terms control over general ones, and a reading that renders a paragraph meaningless is disfavoured.

Contra proferentem — construing against the drafter — is a tie-breaker of last resort in commercial cases between sophisticated parties, not an opening argument.

Practically, ambiguity is a litigation multiplier: it defeats early resolution, opens discovery into negotiation history, and puts the outcome in front of a jury. That cost is the argument for spending an extra hour on the drafting.