What does ensure mean?
Ensure is a transitive verb meaning to make certain that something will happen or be true — to secure or guarantee an outcome through deliberate action. It is a workhorse of formal and professional English, appearing constantly in instructions, contracts, policies, and everyday planning: teams ensure quality, governments ensure safety, cooks ensure the oven is preheated. The verb normally takes either a noun object (ensure accuracy) or a following that-clause (ensure that nothing goes wrong). Its connotations are practical and responsible rather than emotional, implying foresight and care. Writers should distinguish it from assure, which concerns removing a person's doubts, and from insure, which properly relates to insurance policies, though the three words share a common ancestry in the Latin securus, meaning safe or free from care. That shared root also gives us sure and secure, making ensure part of a family of English words all devoted to certainty and protection against risk.
verbTo make certain that something will happen or be the case; to guarantee or secure an outcome.
- To make certain that something happens or is the case; to guarantee.
"The airline took extra precautions to ensure that all passengers arrived safely."
"Regular maintenance will ensure the machinery keeps running smoothly."
"She double-checked the figures to ensure there were no errors in the report."
Ensure and insure were once interchangeable spellings of the same word — the split into 'make certain' versus 'buy a policy' only hardened over centuries of usage.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ensure
Ensure entered English in the late seventeenth century, formed from the adjective sure with the prefix en-, meaning to make or put into a state. Sure itself descends from Old French sur, from Latin securus, meaning free from care or safe. The verbs ensure and insure were used interchangeably for much of their history, and both derive from the same French and Latin stock as assure and secure.
How ensure is actually used
Ensure is neutral-to-formal register and common in business, technical, and official writing. It typically takes a that-clause or a noun object. In careful British and American usage it is preferred over insure for non-financial senses.
Easily confused with ensure
Insure refers specifically to arranging financial insurance against loss, while ensure means making certain of a general outcome; in American English insure is sometimes used in the general sense, but ensure is the safer choice.
Assure is used almost exclusively of removing someone's doubt by telling them something, with a person as its object, whereas ensure makes a thing certain rather than reassuring anyone.