Is it ensure, insure, or assure?
also, through 18c., errour, c.1300, from Old French error "mistake, flaw, defect, heresy," from Latin errorem (nominative error) "a wandering, straying, mistake," from errare "to wander" (see err).
Words for "error" in most Indo-European languages originally meant "wander, go astray" (but cf. Irish dearmad "error," from dermat "a forgetting").
error er·ror (ěr'ər)
A defect or insufficiency in structure or function.
An act, an assertion, or a decision, especially one made in testing a hypothesis, that unintentionally deviates from what is correct, right, or true.
1. A discrepancy between a computed, observed, or measured value or condition and the true, specified, or theoretically correct value or condition.
3. (verb) What a program does when it stops as result of a programming error.