(also in·sure especially in NAmE ) / ɪnˈʃʊə(r); -ˈʃɔː(r); NAmE ɪnˈʃʊr/ verb
to make sure that sth happens or is definite :
[ vn ]
The book ensured his success.
[ v ( that )]
Please ensure (that) all lights are switched off.
[also vnn ]
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WORD ORIGIN
late Middle English (in the senses convince and make safe ): from Anglo-Norman French enseurer , alteration of Old French aseurer , earlier form of assurer , based on Latin ad- to (expressing change) + securus , from se- without + cura care. Compare with insure .