Able to be discovered, found out, or determined with certainty through investigation or evidence.
From ascertain (to determine as true) with the suffix -able (capable of being). First used in English legal documents in the 16th century.
Courts love ascertainable facts because they're the opposite of 'he said, she said'—an ascertainable contract price, age, or date can be verified objectively, making it enforceable in law.
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