in·sure Listen: [ n-shr ]
v. in·sured, in·sur·ing, in·sures
v. tr.
a. To provide or arrange insurance for: a company that insures homeowners and businesses. b. To acquire or have insurance for: insured herself against losses; insured his car for theft.
To make sure, certain, or secure. See Usage Note at assure.
v. intr.
To buy or sell insurance.
en·sure Listen: [ n-shr ]
tr.v. en·sured, en·sur·ing, en·sures
To make sure or certain; insure: Our precautions ensured our safety. See Usage Note at assure.
[Middle English ensuren, from Anglo-Norman enseurer : Old French en-, causative pref. ; see en-1 + Old French seur, secure, variant of sur ; see sure.]
en·close Listen: [ n-klz ] also in·close [ n- ]
tr.v. en·closed, en·clos·ing, en·clos·es
To surround on all sides; close in.
To fence in so as to prevent common use: enclosed the pasture.
To contain, especially so as to envelop or shelter: "Every one of those darkly clustered houses encloses its own secret" (Charles Dickens).
To insert into the same envelope or package: enclose a check with the order.
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[Middle English enclosen, from Old French enclos, past participle of enclore, from Latin incldere, to enclose ; see include.]
Synonyms: enclose, cage, coop, fence, hem1, pen2, wall
These verbs mean to surround and confine within a limited area: cattle enclosed in feedlots; was caged in the office all afternoon; was cooped up in a studio apartment; a garden fenced in by shrubbery; a battalion hemmed in by enemy troops; ships penned up in the harbor; prisoners who were walled in.
in·close Listen: [ n-klz ]
v.
Variant of enclose.
Since you asked the question this way, I never use inclose.