1. discovered or determined with certainty through investigation or inquiry
Usage: past tense and past participle of ‘ascertain’

Examples

• The detective ascertained the suspect’s whereabouts on the night of the crime.
• Scientists have ascertained that the fossil is over 65 million years old.
• The company ascertained the cause of the equipment failure through careful testing.
• After reviewing all the documents, the lawyer ascertained the facts of the case.
• The researchers ascertained that the new treatment was effective.
• Officials ascertained the identity of the victim through dental records.
• The auditor ascertained that all financial records were accurate.