ensure
v.-
1 to make certain (v.) B2 Upper Intermediate Academicto make sure that something happens or is true.
to make certain that a specific outcome, condition, or event occurs. Transitive — typically followed by a 'that' clause or a noun phrase.
ExamplePlease ensure that all the windows are closed before you leave the house.
ExampleThe new safety protocols were designed to ensure that no unauthorised personnel could access the laboratory after hours.
UsageCommonly followed by a 'that' clause; in informal contexts, 'that' is often omitted.
Teacher's tipLearners often confuse 'ensure' with 'insure' (related to money/insurance) or 'assure' (to tell someone something to remove their doubt).
PitfallPlease ensure to lock the door.Please ensure that you lock the door.In formal writing, 'ensure' is usually followed by a 'that' clause rather than an infinitive with 'to'.
From Middle English ensuren, from Anglo-Norman enseurer, from Old French seur (“sure”). Doublet of insure.