Longman Dictionary of Contemporary English homepage

Date: 1500-1600
Language: Old French
Origin: acertainer, from certain

ascertain

verb
     
as‧cer‧tain [intransitive and transitive]
formal to find out something:
A postmortem was ordered to try to ascertain the cause of death.
ascertain whether/what/how etc
Tests were conducted to ascertain whether pollution levels have dropped.
ascertain that
Police had ascertained that the dead man knew his killer.
ascertain something from somebody/something
You should ascertain the level of insurance cover from the car rental company.
ascertainable adverb

Dictionary pictures of the day
Do you know what each of these is called?
What is the word for picture 1? What is the word for picture 2? What is the word for picture 3? What is the word for picture 4?
Click on any of the pictures above to find out what it is called.

Explore our topic dictionary